Calculated Members

I have a reporting services report that I'm creating from an Analysis Services cube. I created two calculated memebers. When I put either one of the calculated members in the report and try to render the query or generate the report, I get an error: Memory Error: Allocation Failure: Not enough storage is avaliable to process this command. I have 21 GB of hard drive space.
I do only have 1 GB or RAM, put I thin that should be enought. Any ideas as to why I get this problem when I run the report including a calculated member? BTW, the report works okay (not great in regards to timing) when I don't include the calculated memebers.
Thanks,Hi
I am facing the exact issue.
Can anyone point me to the right direction?

Thankyou
Vidya|||

We you run the MDX directly against the cube, how many rows are returned (with and without the calculated members)?

|||When i Run the MDX Expression direcly against the cube with the Calculated Measure, i simply get the Error .
when i dont use the Calculated Measure , i get the result in just 2 seconds.

Thankyou
VIdya