We had a issue with the excel web services, when we try to add the excel worksheet to “Excel Web Access Web part” it was showing error message “An error has occurred, please contact your administrator…”. I observe 4 errors in the event log when try to access the page:
|6641||The SSP Timer Job Distribution List Import Job was not run.
Reason: Logon failure: unknown user name or bad password
|5231||Unable to reach Excel Calculation Services|
|5239||There was an error in communicating with Excel Calculation Services|
|5234||No Excel Calculation Services is available in the farm.|
After some research/Google found that these errors are because of the farm service account, then i reset the farm service account credentials using stsadm commands and excel services are working fine.
WSS & SharePoint Server 2007 Password Change via STSADM
Follow these best practices for the MOSS administrative and service accounts:
Hope this helps.