ya thanx eric. got the stem of the problem, its coz i developed my app using mdac2.5 version and few days back i installed mdac2.6 on my machine and i think that caused the problem.
but now i've got stuck in another issues, now i' want to remove mdac2.6 and install 2.5 back. plz help
and also i had installed service pack 4 on my dev. machine now i dont want that sp4 so when i'm uninstalling it(for that complete vss needs to reinstall) still the project is showing sp4 dlls that is not removed from machine ..now how to remove them???
what is the best way to manage different MDAC versions ?

thanx again