The foreign WIFI's may be secure, but that does not always prohibit a 'dead connection'. I haven't tried this with a pronto, but I have seen many an occassion where a WIFI equipped laptop shows a wireless connection to a somewhat protected AP but can't do anything. Basically it is letting you in but most probably is refusing to assign an IP address based on router security or potentially there are MAC or Network filters setup to stop it going any further.

Also have you checked your router/AP to see if it is blocking any ports on the internal or local network?

The other thing I can think of is if your SSID is hidden or if you have a duplicate SSID from another AP in range of the Pronto. A Hidden SSID on some routers can make the pronto go bucky. Rough translation it's got no idea where to go!