Uhm, .I'm in dainn 2 l-point, just after following a marauder....but now the mission seems bugged: the freighter it's just immobile and there no way to get it moving :/
Anyone else have this problem?

Thanks for that, but I finally was able to complete the mission. As you are probably aware it seems like just an extreme case of the "ships emerging from hyperspace refusing to clear the exit area" bug, but the Marauder Freighter takes the effect to previously unheard of extremes. :)
When it finally turned up and then just poodled away from the hyperspace point, I was really worried I was going to blow the mission by being spotted, or messing up somehow, but fortunately I was able to complete it without mishap.
Would you guess there are any factors the player can change that might influence the freighter's behaviour? How long you wait before hiding in the debris, if you are looking at the map screen when the freighter arrives etc?

I couldn't see anything obvious looking at the mission script - it could be an AI avoidance problem, not related to the actual mission script.
It's not surprising that glitches like this can crop up when you consider that the game was designed on machines running a fraction of the speed of modern PCs.
My development PC was an AMD K6-2 350, with a Kyro graphics card. It could run the game about 20fps at 800x600 if you were lucky. I remember seeing the game running on a 1ghz machine with a better graphics card, and was amazed how smoothly it ran.

No offence intended to the game, or its creators, Ravenger. Its just that I like it so much I would spend time trying to find a way past any issues, so that more people can enjoy it.
As I say though I think ithe Wolf's lair stationary freighter problem is connected to the issue where some vessels just start stacking up on the exit of a jump point.

I fully understand! I spent 7 years officially supporting the I-War games, and I want people to play them and enjoy them. It's by far my most favourite game series I ever worked on.
It's a shame when the original developer is no longer around to provide official support - all that expertise that made the game and the knowledge of how to fix it is now gone, or at least virtually inaccessible.
By the way, I've uploaded the mod which bypasses the mission to my I-War paper model website:
[url=http://93.174.141.45/~iwarpm/transfer/BypassWolfsLair.zip]http://93.174.141.45/~iwarpm/transfer/BypassWolfsLair.zip[/url]

I've played through the game maybe five years ago and don't remember having this problem before, but...
I can't remember quite how this mission i supposed to go when the freighter cooperates. I've read the encyclo-walkthrough, and of course Clay says some blurb about sneaking up to the freighter. Is sneaking close actually necessary, and if so, how in the world do you accomplish that? I turned my power down to practically nil (just enough to get the HUD and targeting to work), cruised in at a painfully slow 20 m/s, and still got detected. Fight ensued but my power was way down so that made things interesting... I'll try next with Flight Assist off.
This was using the big corvette. Does a smaller ship help? Is that tug floating in the junk useful for anything (I couldn't remote-command the thing)? Does it screw up the mission if you duke it out with the corvettes? The encylo-walkthrough mentions being quick about it, but I'm not sure what that's supposed to mean. Knowing the mission is tough to get through for technical reasons, I don't want to waste a boat load of time on every attempt if it's not necessary to go in stealthy. Then again, if non-detection is an absolute requirement then I'm doing something wrong.
Speaking of saving some time, here's what I did to shorten the process: Followed some Marauders (after a distress call) to the L-point and got the script from Smith about an uncharted L-point; this puts the Dainn II L-point on your contact list and updates your objectives. I didn't jump through to Dainn II at that time; instead went back to base for the autosave. Launched again and the mission picked up with the Dainn II L-point in the contact list. Followed it and the mission picked up as if I'd tried it all in one shot. At the very least, it saves the time of having to follow some random Marauders to an L-point every time after a distress call.

Update: looks like stealth doesn't matter.
I got through fairly quickly, better than the lather-rinse-repeat some others have dealt with. Here's what I found: Go to the junk pile and wait maybe 20 seconds. The transport will show up shortly after the corvettes. If the transport continues to move after arrival through the L-point (it'll head away from you, roughly in the 2 o'clock direction), then the mission will continue as normal. If the transport instead stops on arrival, then you're screwed; reload your last save and try again.
Don't worry about stealth - it worked for me twice and the corvettes were alerted both times. Here's how to deal with it if the transport moves the way it should: Use F7 to form up with the transport and you'll both go into LDS once you clear the LDSI field around the L-point. After a short bit you'll be hit with an LDSI missile. Use this window of opportunity to toast the four corvettes - do it quickly so the transport doesn't leave without you when the missile-induced LDSI field wears off. It seems like you have about a minute to take care of them. If you don't get all of the corvettes the first time, join up with the transport using F7 again. The remaining corvette(s) will again launch an LDSI missile and you'll have another chance to finish them off before reaching the next scripted location.
I tried shooting the stopped transport to get it moving away from the L-point; it does move again after dumping the cargo. Problem is, the transport heads to a police base and the locals shoot the it to pieces (it went to the same place the two times that I tried it). In other words, restart the mission if the transport just sits there on arrival.

I don't have a fix for the mission, but I have created a mod which allows you to bypass it.
It requires the 'multimod' mod to be installed.
[url=http://93.174.141.45/~iwarpm/transfer/BypassWolfsLair.zip]http://93.174.141.45/~iwarpm/transfer/BypassWolfsLair.zip[/url]

YES!! This Mod allowed me to complete the mission. Thank you very much, Ravenger.
(Random screenshot attached for no particular reason. Enjoy the postcard)

Is there any chance there's a similar mod floating around somewhere for the Corporate Holdings mission?

I can adapt the BypassWolfsLair mod so that it can bypass corporate holdings if you want.

Thanks, but I just figured out a way to get around the corporate holdings glitch, by simply jumping back through the L-point ahead of the convoy right after despatching the enemies. Thanks for the offer though!

Did you accidentally experience the same problem than I? Corporate Holdings has three different outcomes for me. Either my ships explodes as soon as I jump into the minefield, I fail to protect the freighters when the swarms of corvettes attack them or if I save them but they get too close to the LaGrange point the game begins to slow down and finally crashes. I had no CTDs or any kind of stability problem until this mission.

I got some strange graphics glitch where my view would suddenly change to a side-view from my ship and not be changeable, then a little while later the screen would freeze and I'd have to terminate the game via Task Manager. It usually happened right as the transports approached the LaGrange point. So by racing ahead of them and going through first once the enemies were dead I avoided it--I was afraid I'd fail the mission because I didn't wait for Jarvis to actually tell me to leave the system, but as long as you leave no enemies behind you just have to wait for the convoy to join you in Mwawi and get Jarvis' thanks.

I've finally managed to finish Corporate Holdings. Thanks for your tip, it worked very well.