I was using Ubuntu 8.04 with installed Perl 5.8.8. I had installed Bugzilla 3.4.4 with some custom scripts and it was working fine. I had to upgrade Ubuntu from 8.04 to 10.04 and automatically Perl is also upgraded from Perl 5.8 to 5.10. Now, accessing Bugzilla displays an error message related to Perl module. While trying to run checksetup.pl, I am getting the following error message: root@cvsnew:/var/www/bugzilla-3.4# perl checksetup.pl * This is Bugzilla 3.4.3 on perl 5.10.1 * Running on Linux 2.6.32-24-generic-pae #39-Ubuntu SMP Wed Jul 28 07:39:26 UTC 2010 Checking perl modules... Checking for CGI.pm (v3.33) ok: found v3.48 perl: symbol lookup error: lib/i486-linux-gnu-thread-multi/auto/Digest/SHA/SHA.so: undefined symbol: Perl_Tstack_sp_ptr Accessing Bugzilla throws : "500 Internal Server Error". I explored this issue and found that this issue has come up because upgrading Ubuntu upgrades Perl 5.8 to 5.10 automatically. It seems like Perl 5.10.1 isn't binary compatible with the previous. Now, I want to uninstall Perl 5.10.1 and Install Perl 5.8.8 on my Ubuntu 10.04 box. I will appreciate if someone has already done that or share the required steps/commands to do it.