I have been told that a machine with .NET on it should not be used to build VB6 executables.

I would like to know what the specific problem areas are.

Is there a list somewhere of the errors or problems that will be encountered?

Just to be clear, there are 2 different scenarios.
1) VB6 compiler installed on a machine that has the .NET framework installed as well
   - this should work fine with VB6 code
2) VB .NET compiler installed (not VB6 compiler) while trying to work with VB6 code
   - due to the large number of changes made the the VB language with the transition to .NET, you will likely end up with more errors than usable code even after using the builtin conversion process
   - after the conversion process you will have to go over the existing code with a fine tooth comb to make sure it meets the coding requirements of VB .NET b/c they are very different than VB6 and the converter will not be able to catch all of those changes for existing VB6 code

But the question is regarding the problems that might be encoutnered compiling a VB6 application on a machine that has everything necessary also to create VB.NET applications.

This is not regarding using .NET to try to compile a previously-VB6 application, or any cross-version operation like that.

If I have VB6 on a machine, and am using that to create one application, and I am using VB.NET on the same machine to create different applications; do you know of any issues that that would raise with the [u]VB6</u> fuctionality?