QTR-Quadtone RIP

I just installed version 2.4.2 over 2.2. I had created a number of 
curves for a custom ink set in the past. I'm now changing to a 
standard ink set so I just want to linearize some existing curves.

I click "curve creation" > file open,  I clear the linearization 
values & click > file> save as (new name) then click "Create Curve". 
I get the error message –

"Qdotgain did not return a valid curve at quadprofile.pl line 88
Curve Creation failed."

I've tried uninstalling and reinstalling the software.
I'm running Windows XP home edition 

Any help would be appreciated,

Thanks
Bob