Newbie - cannot find file for class - how to debug?

Fri Sep 1 00:39:00 GMT 2006

I'm trying to compile my .class files into native byte code and I'm running into the following messages:
...: error: cannot find file for class...
I've tried adding the jar containing the missing classes into the classpath argument, "--classpath".  I've also tried adding it to the list of "source" files at the end of the gcj command, with each source file separated by a space.  Still, these classes cannot be found.
I know the -classpath variable I've set is taking affect, because there's another jar that I've added to the classpath parameter which, when removed, causes a different class to not be found.
Is there a good way to debug this?  Can I print to the console where gcj is looking for the class?
Thanks.
Scott