Hello,
LocationInfo.isLocationSourceAvailable(LocationInfo.GEOLOCATION_MODE_WLAN);
will return true only if the service record for WLAN Geolocation is present on the device.
Sicne you mentioned that you somtimes got WLAN-fix before on the same device, how did you confirm that it was a wlan fix?
Have you changed your carrier recently? That can wipe your old service records and get new one and the new carrier may not have RIM's WLAN geolocation enabled. However, most (if not all) of the carriers should have it enabled.
Cheers.
Shadid
