"Aborting launch due to failed build. " Message

Hi,

When I try and launch the simulator, I get the message "Aborting launch due to failed build." The project successfully builds (I get the "BUILD: Complete" message), but running generates this error.

The bizarre thing, is that I have 6 projects are they all give the same message. Even more bizarre, is all 6 projects on other PC's work perfectly.

I've tried running the build in the command-line and no warnings or errors also appear.

I am really keen to get my main PC running and testing, anybody any ideas?

Cheers
Chris