svchost.exe – application error

One of my users gets this message when trying to opening an app when He is on the network.

“The Instruction at “0x1000e765″ referenced memory at 0x00000000”. The memory could not be “read”.
Click on OK to terminate the program
Click on CANCEL to debug the program”

What could be causing this problem. I heard that AVENTAIL may be the cause… any ideas??

p.s. The computer works fine if its a standalone.

thanks in advances Guys and Gals