gpasm: Assertion `state.obj.debug_file != ((void *)0)' failed

Running gpasm with the "--debug-info" switch on some assembly code fails with 
the assertion:

gpasm: coff.c:388: coff_linenum: Assertion `state.obj.debug_file != ((void *)
0)' failed.

Here is the simplest example (run with "gpasm --object --debug-info 
input.asm") -

------------
list p=16f84
STARTUP	code
nop
-----------

This is using the latest gputils from anon-cvs.

I tried debugging gpasm to work out what was happening, but got lost (although 
interestingly came across the comment "FIXME: need line_number? this one will 
be wrong coff_linenum(1)" in directive.c, and the assertion is failing on 
calling coff_linenum(1)). Hopefully someone else can shed some light on this?

Regards,
David Saxton