[Nigel Turnbull]

I installed Adobe premier CS3 suite with a dual monitor setup and ‘Export Adobe Encoder’ worked fine.
I later changed to a single monitor setup and the ‘export Adobe Encoder’ window did not appear.
Solution:
Shut down Premier — you may have to use ‘ctrl alt delete’ to force it to close.
Open ‘Windows Explorer’.
(MAKE SURE THAT HIDDEN FILES ARE VISIBLE in Windows Explorer) — MENU/TOOLS/View/(bullet) Show Hidden Files and Folders.
Go to c: DOCUMENTS AND SETTINGS/MY NAME/APPLICATION DATA/ADOBE/PREMIER PRO/3.0
Do not delete the directory/folder called 3.0 — only delete the contents.
Delete everything in the directory/folder called 3.0
Premier/ Export Adobe Encoder, is now back on the planet.
Sorry if someone else has already posted this solution. I have not read all the posts.
Enjoy. This might save you the two days it took me to figure it out.