duplicate applications

[Tom]

When I right click on a file to get Open with,
I now have duplicated apps listed. Sometimes three.
Then if I select one, lets say Preview, a second Preview icon appears in the Dock.

When looking at the applications folder, I only see one of each.
Could this have something to do with using SD?
Thanks.
http://img179.imageshack.us/img179/4433/picture3mo7.gif

[Tom]

Used OnyX to reset the launch services database.
That fixed it.