registration problem

some of my new registered member are complaining when they register and log in they recieve this error message:

phpBB : Critical Error

User not found in IM preferences table

Can you please let me know how to correct this problem?

Thank you kindly
Melissa

Have a look at this tutorial. It has answers about this.
http://www.phpbbsmith.com/mb/cms_view_article.php?aid=21

Okay l have followed the instructions to your above link.....but my SQL Queries keep telling me that they are duplicate entries..

I only have one member with this problem so far....can not add her to the im preferences as it says she is already thier???

But she is still recieving the error message

Try making the code change in the Alternate Solution section of the tutorial. If they really aren't in the database, as the script seems to think, that should add them for certain.