I've heard that once one of your primary skills reach 100, you will no longer be able to level up. Is this true, or is there something else I should know about?

That is a bug that is fixed by the later patches.

There is also an add-on program that allows skills (and abilities) to rise to 127, rather than 100. It is called dfskills, and should be easy enough to find.

Right, with the later patches you can raise each skill to 100. This gives a max level around 24.

FWIW, it's possible to get multiple skills to 100 without a patch (IMO this was more likely a feature, as it would require extra code to make happen). How to do this I at this time leave as an exercise for the reader, although I believe I've explained how to do it in some other thread.

With the dfskills program that I mentioned above, my highest level character (the one that I use as my screen name) rose to 45th level. At that point, the amount of repetitions of skill use needed to raise them became ridiculous. The program doesn't alter the mechanic within the game that makes higher scores progressively more difficult to advance, it just makes it theoretically possible. :banghead:

Thanks.