nw 6.5 sp3. iPrint client 4.11. XP sp2. NW client 4.91 sp91

When I try to install a printer from http://server/ipp I get an error 126.

Adter reading posts, one solutions was to make sure the path environment
statement was correct. This work ONCE for me.

Another solution was to reinstall the NW client. I did that also.

I can install the printer manual and it works (NDPS printer).

Any other things to look at??