Ok, first off I have to use the trick with adding -dontforceminreq to a shortcut to get this running, not sure if it has anything to do with it, but here's the problem:

When I go into the video settings I can change everything as expected except for the texture settings where the slider won't move at all. Also, when trying to change it, the text above the slider, which should say 'low', changes to some weird number (like 999998 or something like that). The slider does not move at all.

I am running this on a laptop with a mobility radeon hd 3470, not sure if it has anything to do with this issue as it is of course a weak gpu, but the game runs smoothly enough with lighting, shadows at medium so I would like to try to up the texture settings if possible.

Thanks in advance for your help.

Unless something changed recently,using -dontforeceminreqs switch indeed disables texture settings.
You may try looking through official Witcher forums, that issue was pretty well known.

Are you sure you need the -dontforceminreqs setting? (If the game simply refuses to start without it, then you do. But I would have thought the 3470 would not need it.)

If you use -dontforceminreqs, then indeed you cannot change texture settings.

If you have a really low-end GPU, increasing the texture quality may be counterproductive anyway. But a 3470 should be good enough to allow you a little increase.

What are the specs for the rest of your system? Although this is usually caused by having an older GPU, you could theoretically trigger the error message by not having a fast enough processor or enough RAM.

Well it is a core2duo 2.10 ghz and 3 gb ram.

On system requirements lab it passes everything.

Come to think of it, maybe it is because I have modded ati drivers (because toshiba does not allow updating of their drivers, I had to resort to this if I wanted new drivers).