Try and buy another cleaning cassette, use it once. Once youve used the cleaning cassette, dont use the same normal cassette that you were recording onto before. Buy a new one. This way, all the dirt and oxides on the old tape wont be instantly transferred onto the heads that you just cleaned.
If theres no change then your heads will probably need replacing in the camcorder. This needs to be done buy a qualified repair person and I dont know how much this costs.
Unfortunately Im in the same situation as you at the moment.
Rhys, June 2008