user extensions compatibility with IE

My user-extensions are not recognized in ie....can anyone tell me why???????
every time I try to use a user-extension file, it says 'Unknown command'
Did any one else have such problems?
I am waiting for a response

wt cmd u r using??

the same command that i wrote in javascript and included as a function in the user extensions.js file

*iexplore.... hav u used this?

yes i did