Nothing more specific. You could turn on the SDEINTERCEPT on the client and see where the error is occurring? Deciphering Errors within ArcSDE | Support Services Blog
When was the last time that a compress successfully completed?
What version of ArcGIS client are you using?
Are you using 3-tier connection or direct connections?
Can you provide a workflow for the compress?
Can the SDE user add features to a map and select over 100 of them? Try to select 200+ and see of that works?
--- George T.