Scroll down this page and use the error fixer,it may sort your problem click here
After a quick look around it seems to point to Passport Identity Client Run-time Library (IDCRL) dll problem.
If the above fix does not work for you,try uninstalling msn run Regscrub xp click here reboot and then try a fresh install of Messenger 7.5
click here or click here
Hope this helps