I had been trying to upgrade my cpanel version with upcp last day.
My current version – 11.34
Targetted version – 11.38
Tried many times, but each time it was stuck after the following error.
[20130801.235456]  ! Bad archive: CPAN-SQLite-0.203.tar.gz
[20130801.235456]  ! Failed to unpack CPAN-SQLite-0.203.tar.gz: no directory
Upon searching, I identified the problem is with the SQLite module. So I killed the currently running process, updated sqlite and ran again and hurrayyyy it worked.
ps aux | grep upcp – will list the upcp processes running
kill -9 pid – kill that process where pid is the process id listed in the above command output
cpan -i CPAN::SQLite - install the cpanel sqlite module directly
/scripts/upcp --force - run upcp again