IllegalAccessError: cross-loader access from pre-verifed class in MapActivity

I have a big problem.

When I lauch my MapActivity this launch the ilegal argument. I think that i check all

1) add map.jar from api 3 to eclipse 2) I obtain a api key 3) In androidmanifest I have putted the uses-library and te internet permision 4) I launch the google api emulator for api开发者_C百科 3. 5) I dont know that i can try.

Please, any idea? this can't be too dificult, I can't belive. Sure that it is a stupid thing :S

I found the problems, I know that this is a stupid error. The problem was that I include de map.jar directly to build path in eclipse and I dont selected the target inside the properties->android. Holy shit.

Thanks for all,