Flash crashing on export for actionscript

Help!!

I am having a problem and I wondered whether somebody might be able to help me. I am creating a movieclip which I have set the ‘export for actionscript’. In the class input I am putting my class location, which is: uk.co.domain.baseButton.

When I click the tick to check the path, Flash Quits on me.

Any ideas?

Cheers