Database warning?

Hi

I have a warning message coming up once in a while, and I am not so good at the databases, so I have to ask for a little help.

I took a screenshot of the warning, and it can be viewed here www.studmanu.dk/pic5.png

The warning appears multiple times, so I just took a screenshot of part of it. It seems like it's the same warning for each of my installed themes, including deco which is my main theme.

I don't know if it is a problem with the theme, but in case it is, I thought I would post it here.

Hope someone can make sense of it?

Jacob