Crash in address search upon clicking on [Email Write]

I run the Thunderbird Portable (TP) on a TOSHIBA dynabook SS portable PC under Windows VISTA. I have 1GB of RAM, more than 1GHz frequency, and 80GB HDD.

When clicking on [Email Write] icon to bring up the email write window, then entering addressee's name in the address searchwindow crashes the TP. This crash does not occur the first time upon starting the TP, but the 2nd time on, it definitely crashes. I deleted , and from the profile subdirectory and restart the TP, but it did not solve the problem. This looks like a result of a SW bug, which I hope the engineers in charge will fix asap. It's really annoying because I have restart the TP every time.