I have a ZTE which works fine out of the box, so I don't think it's a driver/pclos problem. I suspect it's a difference between how pclos thinks your access point needs to be set up and the actual set up - could be something as simple as the phone number being changed.
As it works in Windows, have you tried connecting in Windows and then opening up all the network connection properties to see how it's set up there? Then you could go into "unlisted - edit manually" and set it up the same.
Worth a try.