try going to your HM2 folder under Program Files / Holdem Manager.
make sure (if you're in windows) both hudfuncapp.exe (or somethin) and HoldemManager.exe are run as administrator.
To do this [Right click the file, properties, run as admin is under one of the tabs]
after that (not before) turn off user account control.
if u have UAC turned off already you probably wont be able to tick the administrator box to run those files as Admin. Simply (not simply) turn on UAC, restart, run both as admin, turn off UAC, restart... partially lose your sanity... and then rejoice if HM2 works without a hitch.
if that doesn't work post back. fair chance I cant help with everything. The HM2 forums are usually very keen to help.