There has been quite a few changes in Servicemix 4.1 - see our release notes at http://fusesource.com/wiki/display/ProdInfo/FUSEESBv4.1ReleaseNotes
Also is it possible you can send in your servicemix log file - when you say hotdeploy - are you deploying your Service Assembly directly in ?
Yes I was dropping the SA jar file in the deploy folder.
Can you try drop in the zip file as the jar won't contain all your service units ?
Let me know if that fixes the issue.
Also if you use the osgi/install command from README to install the demo - does it work for you ?