For the impatient:
New version. Should not freeze if Buxfer is slow to respond or if you forget to plug in the cable. Also some better handling of special characters while talking to the server.
For the curious:
Buxfer seemed to have had a bit of trouble with site slowness, which exposed my cluelessness in developing widgets that connect to web services (as in, forgot to consider timeouts of XMLHttpRequests).
As I said before, the code is up on google code, so feel free to browse around, all three of you who are reading this :)