Comment 4 for bug 46530

This may not be totally pertinent. But when I tried to install gdb, it turned out I already had it... but then the error cropped up again, as though the error is unrelated to installation, and is just a part of dpkg

Reading package lists... Done
Building dependency tree... Done
gdb is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
Need to get 0B of archives.
After unpacking 0B of additional disk space will be used.
dpkg: ../../src/packages.c:191: process_queue: Assertion `dependtry <= 4' failed.
E: Sub-process /usr/bin/dpkg exited unexpectedly

If that helps diagnose the problem at all, as for the backtrace, I'll have that in a moment.

cheers
-Dan