Added this webpart to my SharePoint Online site. It says Web Part Error: Sandboxed code execution request failed.

I am getting this same error, did you get it resolved.

Did you upload the .wsp to the solution gallery. You could also open support request with Microsoft Support. Not sure what could be causing this. May be a little more information can be help me look at the source code.

Exact same problem for me.  What information would be relevant to you to troubleshoot?

MS Support would help with a sandbox third party solution?  That would surprise me very much.

Need to check resources allocated to the solution. May be the resources are max'ed out on the sandbox solution

I got the same error message, and the sky drive connector properties doesn't appear inside the webpart. Have you found a solution ?