Update MIF in Quartus 8.0 (w/ Nios)

Is anyone else having issues with the "Update Memory Initialization File" command in Quartus 8.0? I used to be able to run that command (followed by the Assember) after rebuilding my Nios project, and the resulting .sof file would be updated to reflect the changes in Nios. Now, when I update my C code, recompile, and then run Update MIF, I get errors stating that it cannot find any files to update. I haven't changed any file paths since my update from 7.2, so I'm a little confused about what might be causing this. Any suggestions would be appreciated!

Thanks,

Jeff