While Saving the excel using workbook.saveAs getting the Exception from HRESULT: 0x800A03EC 02-18-2010, 1:59 AM

1. Login to the server as a administrator. 
2. Go to "Start" -> "Run" and enter "taskmgr" 
3. Go to the process tab in task manager and check "Show Processes from all 
users" 
4. If there are any "Excel.exe" entries on the list, right click on the 
entry and select "End Process" 
5. Close task manager. 
6. Go to "Start" -> "Run" and enter "services.msc" 
7. Stop the service automating Excel if it is running. 
8. Go to "Start" -> "Run" and enter "dcomcnfg" 
9. This will bring up the component services window, expand out "Console 
Root" -> "Computers" -> "DCOM Config" 
10. Find "Microsoft Excel Application" in the list of components. 
11. Right click on the entry and select "Properties" 
12. Go to the "Identity" tab on the properties dialog. 
13. Select "The interactive user." 
14. Click the "OK" button. 
15. Switch to the services console 
16. Start the service automating Excel17. Test you application again.

If Not

my service starts under local Administrator account
- on DCOM Config > MS Excel Application > Identity tab I've selected "This 
user" option and also entered Administrator's account