Okay I have a couple of threads for you to check out.
First things to try are:
1) Rename AVI folder to AVI_back
2) Make sure no programs are running in the background
3) reduce the acceleration of your sound card.
If they do not work take a look at these threads.
http://www.europa-universalis.com/forum/showthread.php?threadid=63139
http://www.europa-universalis.com/forum/showthread.php?threadid=59836
First things to try are:
1) Rename AVI folder to AVI_back
2) Make sure no programs are running in the background
3) reduce the acceleration of your sound card.
If they do not work take a look at these threads.
http://www.europa-universalis.com/forum/showthread.php?threadid=63139
http://www.europa-universalis.com/forum/showthread.php?threadid=59836