Thanks for the fast unswer, but I don't have Dreamweaver, only Photoshop CS5.1.
Only Photoshop CS5.1 is shown on the left side as explaind in #2.
The solution refers to "error U44M1P7" and I have "error U44M1P29"!!
Adobe Extension Manager is a component that gets installed with multiple Adobe applications.
The steps in this document help repairing installation of the Extension Manager which seems to be the actual problem looking at the error message you are receiving.
In the coloumn to the left, you can select the product you are using which is Photoshop.
You can also uninstall Adobe Extension manager and use the original installation media to repair the installation as mentioned in the link.
Do let us know if you continue to face the same issue.