Re:Problems with Rapture.
On Vista and Windows 7 Microsoft has changed the location where user data is stored for profiles. On XP it was under "C:\Documents and Settings\", but on Vista/Win7 it is in "C:\Users\".
When you launch SONAR on the new computer, are you launching it with the option "Run as Administrator"? This can be done by setting the option in the properties for the icon, or it can be done by selecting the option at launch time, right-clicking, and selecting "Run as Administrator" instead.
Have you downloaded the most recent drivers for the 1820M directly from Emu and installed them onto your new machine? If not and you're using drivers that come with the unit on disc then try getting newer drivers from Emu's web site. Also, what driver mode are you using in SONAR (ASIO, WDM)?