I suggest unistall V1.7 cause it is tested and works fro 1.3.9 installations and try an older version like 1.6 or 1.6.1.
The other option is to update zencart installation :)
If you're not upgrading for awhile, a good idea is to try one of the following tips ---> http://www.data-diggers.com/advanced...formance-tips/
Remember before any change!!! Backup to be able to go back!
My Online Store thanks to Zen Cart
If everything else fails.... read the f@#$%ing manual :)
And always remember before any change!!! Backup to be able to go back!