Can you Reload ThingWorx and in Composer, go to the Import/Export tab. Under Extensions, go to Manage and verify whether or not the extension package was uploaded. I also have a few questions. What version of Tomcat and Java are you currently using and are you seeing any errors in the Application log after importing the extension packages. If possible, can you upload the app log to your File Repository?
I reloaded Thingworx as well as Composer. Also i checked under Manage Extensions, i can see that Mail Server Extension is imported successfully. I am using tomcat 7 and JRE7 .
Also, I can not see any error reported in application log. Can you please explain how to upload application log to file repository?