Read this... http://forums.cnet.com/5208-7594_102-0.html?messageID=3292666
It worked for me - and for others with different Sony camcorders getting the same (and other) error codes.
You can search the web - and find similar anecdotal evidence. I was reluctance, first, but basically had nothing to lose since the camcorder would not work. My remaining alternatives were to send the camcorder to Sony for repair or replace the camcorder. So I took the tape out, made sure the camera was off, and the tape door closed... and while securely holding the camcorder from the top in my right hand, smacked the bottom of the camcorder with my left hand. This was about a year and a half ago... The camcorder has been working correctly since being smacked.
I hope this works for you. too.
I have a beach video that will not play. I get the "re-insert cassette" warning. I have tried all Sony recommended tips. The moisture warning came on first and later the cassette warning and no function. Maybe a sensor is affecting both the moisture warning and controls cassette/warning, maybe not The moisture warning is way too sensitive and has come on before. I am advanced in electronics and might could fix this if I had a manual or parts breakdown...SOMETHING! Any links to knowledge or ideas would be appreciated!