I was having nightmares with my x51v after switching from a Palm and was just about to give it all up as a bad idea and go back to Palm but...
I don't know what made me do this because I have tried just about every trick in the book to get my Axim connected but I seem to have found a way to do it (well, it's worked first time every time so far). What I do is switch off my anti virus and firewall and then (as I use XP) log off. I log straight back on and hey presto I'm connected.
You know, I'm going to be gutted if I've now jinxed my laptop
Hope this helps somebody somewhere!
Craig