VMware vSphere client 4.0 crashes when trying to upload a file to datastore

 Suddenly my VMware vSphere client version 4.0.0 started to crash when I try to upload a file to the datastore. This happens on both my Windows Vista and XP boxes running the VMware vSphere client.

The problem is similar to the one described in this KB article concering Windows 7 clients. However, the solution is the same. The VMware vSphere client does not crash if it is started by right clicking and runing it as administrator.