General Error (216)? What is that?

I am trying to correct bad sound and when I try to "send to" from Final cut Pro to Soundtrack pro I get the error "General Error (216)".
Incidentally, when I import this isolated aif file into Soundtrack pro (from the original recording, not through FCP) I CAN see it and work on it. Weird, huh?
Any thoughts? Thank you.

10.5.7, 2 x2.66 ghz dual core mac 1.1, 8 gigs ram, fcp 6.0.6, soundtrack pro 2.0.2.