Since I filed this bug report, I installed the final version of Ubuntu 10.04 LTS onto my laptop. I tested Thunderbird in the same configuration as above and it worked fine. I installed the final version of Ubuntu 10.04 LTS onto my desktop, the one that I filed this bug report on, and thunderbird now works fine there too. Must have been something specific to the release candidate.
Since I filed this bug report, I installed the final version of Ubuntu 10.04 LTS onto my laptop. I tested Thunderbird in the same configuration as above and it worked fine. I installed the final version of Ubuntu 10.04 LTS onto my desktop, the one that I filed this bug report on, and thunderbird now works fine there too. Must have been something specific to the release candidate.
This bug report can be closed.
Thanks!