Please help us to help you by giving a more complete description of the problem --
What database are you using? Which version, service pack/patches?
What version of ArcSDE are you using? Which service pack and/or patches?
What ArcSDE client are you using to pan & zoom? Which version, service pack/patches?
What geometry storage type are you using? What does 'sdelayer -o describe_long' report?
How did you populate the data? What does 'sdetable -o describe' report for the table?
Has this never worked, or did the failures start recently?
Have you received any relevant database error messages recently?
- V