[TYPO3-english] GPvar only works when logged in?

[Scotty C]

Hey everyone,
Another day, another question :-P
Pretty simple this time - I have a page with a URL:
www.mydomain.ca/?553&temp_name=some_value
The only TS code on PID 553 is:
page = PAGEpage.10 = TEXTpage.10.data = GP : temp_name
Now, it works perfectly ... when I'm logged into the backend. The second I logout, it doesn't work at all.
Thoughts? (thanks again!)-Scott.