1.151.1. RHBA-2010:0900: bug fix update
An updated thunderbird package that fixes a bug is now available for Red Hat Enterprise Linux 5.
* Previously, clicking the "Load" button in the Device Manager configuration dialog did not not open an appropriate dialog window, rendering user unable to load a PKCS#11 (Public-Key Cryptography Standard) device. This error has been fixed, and PKCS#11 devices can now be loaded as expected. ( BZ#649251
Users of Thunderbird are advised to upgrade to this updated package, which resolves this issue.