Proxy Desktop: explorer.exe - Application error

I have a laptop running Windows XP, the configuration is unimportant. When I close Windows Explorer, I get a popup warning stating "Proxy Desktop: explorer.exe - Application error, referenced instruction 0x01e8422a..." to which I hit close. I checked the solution to uncheck Tools > Folder Options > View > Launch folder windows in a separate process, but that was not applicable. I checked my startup programs and have no unusual programs starting or running from there. Is there a registry key problem that I am not seeing? I didn't feel like spending all day looking at every Google link...