Having trouble with 'unit'

[MattyGG]

Uh...i keep coming across programs that use unit...but every time that i try to run them an error comes up saying "Cannot have unit as main program" Does anyone know what the problem might be?

[Cervantes]

Are you trying to run your unit? ie. by hitting F1. If so, you shouldn't be. Instead, what you do it save it as a .tu and import it into your main program, which you can run using F1.