After having rooted my Desire, it refuses to send and recieve MMS while on WiFi (with WiFi off MMS work). It says "Unable to send MMS, generic error!". I'm using the stock rooted ROM and my MMS settings are correct. Also, under APN type for the main internet APN I have set default, as it should be. I did some googling and it seems it's quite a common issue. Sadly so far, noone has resolved it and it's carrier inspecific. And yes, yesterday before my Desire was rooted, it used to sent MMS with WiFi just fine. Seems like a nasty bug.