OK.. so here is what i did, and now it seems to be working perfectly fine, even with the charger connected i can switch on and off at any time.. no issues.

just follow this thread http://talk.maemo.org/showthread.php?t=60567

i get the same problem... for some reason if i plug in my car charger 1st, th transmitter will noy work. but if i start the transmitter 1st and then plug in the charger, i have no problem..

i also have another similar problem im curious to know if anybody else is experiencing... many times i'll connect a usb cable to the n900 (whether it may be the wall charger, data cable, or car charger) and i know the fm transmitter will not work. but many times, i will unplug the cable and i still get the same error message... it would be as if the cable was still connected. the only way to fix this would be to reboot, which can be inconvenient..
im just wondering if this is a bug, hopefully with a fix, or if theres something i do wrong...

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