I am playing the original game with DosBox through DFend. I am having a problem where at some point the colony stops producing comodities. If I keep playing I build up lots of wood and metal, but it never shows commodities as being produced the next turn. I can still buy them from the mother country to keep building, but that is a poor way of playing the game, and really spoils the fun. Anyone else see this problem? I'm wondering if buying the GOG version will fix it or if there is something else I can do.

The problem is with GOODS, not commodities. I think I got terms confused between CNW and Colonization.

Do you have all the commerce buildings required to produce the goods?

Even with plenty of wood and metal stored I also had this problem several times and it usually occurs in the first city built and rarely in the other cities. The commerce buildings may not produce any thing for several turns then start producing or suddenly stop producing for no reason even if more than enough wood and metal are available.
You may have better luck by putting some commerce buildings in another city.
Edit - Problem still occurs even though there is plenty of extra workers, lots of extra food, lots of extra wood and metal.

As I just posted in another forum:
Possible reasons:
You are not leaving enough resources at the end of each turn. Commerce's consume raw materials (1 wood and 1 metal) to produce goods. They need to be in your supplies at the end of the turn. Not incoming next turn.
You do not have a high enough population to workforce ratio. Try building ore houses. Look in the population tab of your city to what your free labor is. Make sure it is a positive number.
Your colony is starving. Build more farms or trade / buy crops. Hungry workers wont work.
Unfortunately Commerce's are the first building to suffer from any of these problems.

I believe commerce's also consume 1 crop as well along with the wood and metal, i was told on gamefaqs anywho. But yeah no food/workers is another reason why. Or the game just doesn't want to work for some reason. /shrug

I am pretty sure that when your colony grows you have not enough crops and that is the reason goods are not produced. It takes metal, wood and crops to produce goods at the end of the turn. Just as MIlesy mentions.
I do not think there is anything wrong with your game, but that buying sth on gog.com is always a good idea, just to support the portal, am i wrong? :)

The last couple posters are on the right track, but the specific formulas posted are incorrect and one important detail is missing.

"Mysterious" failures to produce goods are almost always caused by crops shortages. People will eat the crops before they use them to produce goods, and people eat before the crops are harvested, so if you have 150 crops on hand and a population of 15000 people, there will be zero crops left for goods production. When currently on-hand crops are near the level required to feed a colony, goods production will sporadically start and stop as food becomes available. You may be suffering from minor starvation too, make sure that each colony has crops = (population/100) + (commerce building levels) + 1. (The +1 is because food consumption is rounded up: 101 people eat 2 crops.)

Commerce buildings consume 1 each of wood, metal, and crops per level of the commerce building. The output of the commerce buildings are 1, 3, 7, and 12 goods, which results in a cost of goods that varies from 3 basic resources to one good to 12 basic resources for 12 goods.

In my experience, commerce buildings are the last buildings to suffer from population shortages. I don't know if this is because they are excepted from that limitation or because they employ fewer workers (the largest employers are the first hit by personnel shortages) -- the only way to tell for sure would be to build a colony that was almost entirely commerce buildings, import a large surplus of wood, metal, & crops, then destroy most of the houses or build lots of settlers to decrease the population and see what happens to goods production.

Giles is correct. It took me SO long to figure it out on my own though. One of the more aggravating things about this game and no satisfaction when I finally figured it out.