I was able to load applications on the 3660 in the following way :-
1) Connect the 3660 to a PC using a blue tooth.
2) Go to normal Windows Explorer and right click on the .jar file which you want to install.
3) In the SEND TO option select the BlueTooth option.
4) Then select the appropriate blue tooth connected device (3660)
5) The .jar file flies smoothly into the 3660, as an SMS and asks for installation. (and gets installed perfectly)
I was facing problems while installing applications using a bluetooth and Nokia PC Suite for 3660
I dont know if this is the right way to install programs....but I could get my MIDlets running very smoothly...so thought of reporting on the group and knowing if anyone else had similiar problems with the Nokia PC Suite for 3660.