Hi,
What version of the extension library are you using and have you unzipped the updateSite.zip to "C:\\Data\domino\workspace\applications\eclipse" ? What plugins are in this directory C:\\Data\domino\workspace\applications\eclipse\plugins ?
Are there any messages in the console when you run "tell http osgi ss com.ibm.xsp.extlib" , can you also try "tell http osgi diag com.ibm.xsp.extlib" , the latter should tell you if you are missing any dependent plugins.
Padraic