Generating Documentation for RoboHelp 8

I am trying to create printed documentation for a

medium sized WebHelp project. I was initially able to generate it and attach it to the Print option in the Menu of the compiled project - since then however the documentation won't generate and gives me an error that it could not be completed. It asks me to read the "compliation" error for more details:

1. I don't see the compilation error displayed anywhere - can you tell me where this error is displayed?

2. Is there a common problem why documentation will not compile in RoboHelp 8 after you have successfully done so at least once?