If you back on this thread the information needed to fix your problem is there - around page 3 or 4. The crux of the fix is
1. Make sure you have the most current version of Form 8801.
2. Delete your current Form 8801 (not sure this is necessary, but I did it).
3. Go back and re-enter your information for the tax credit manually into Form 6251. It appears that either the fix to 8801 deleted this information or there was a bug in the initial loading of information from last year's TT file.
4. This should allow your 8801 to calculate properly (check to make sure things are as they should be) and not get a federal error.
