Windows Explorer hangs

I sometimes use the context menu in windows explorer to upload files using SmartFTP.

When I do the explorer window I used hangs and I have to log out and in again for it to die.

I've searched the forums but didn't find anything relevant.

System info:
+- System -----------------------------
Microsoft Windows Vista Business Edition
Service Pack 1 (Build 6001)

CPU Speed : 1995 MHz
Total Memory : 2006 MB
Free Memory : 837 MB

+- SmartFTP ---------------------------
Version : 4.0.1049.0
Time Stamp : 2009-09-20 17:55:23
Platform : x86
Id : 400054750
Maintenance : 2012-09-23
Days in use : 359

+- Language ---------------------------
en-US

+- Internet Explorer ------------------
Version : 8.0.6001.18828

+- Winsock ----------------------------
Winsock : 2.2

Please upgrade to the latest version and try again.