Perhaps if you were to tell us how your program opens and prints the attachments using Adobe it would be easier to find a solution.
If you're Shell-ing to execute the Adobe print, then you can gain access to the Process ID under which Adobe is running. With the Process ID you can use Windows DLL functions to end the process. This can get a bit tricky because you will want Adobe to finish printing before you close it.
If you're creating an object out of an Adobe Reference, e.g. Set objAdobe = CreateObject("???"), then it might be a simple matter of setting that object to Nothing when Adobe has finished printing.
Randall J Weers
Membership Vice President
Pacific NorthWest Access Developers Group