Syntax error

I have an old AS2 application that I am updating to AS3. When I run the application I get an error

1087: Syntax error: extra characters found after end of program.

It refers to Frame 21, line 1 and the source sited in the compile out box window is: on (release) {

But when I go to Frame 21, line 1, I don’t see any on(release) functions if I search the action script for that frame there are no on (release) { functions. If I double click the error it usually takes me to the spot in the code where the error is located but it doesn’t do that either. So what is this error telling me? How do I find the on (release) { function it’s complaining about?