Take, for example, error number 4000.
In my practice, I came across several instances of its occurrence:
1. Notes error: The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists.
2. Notes error: Network operation did not complete in a reasonable amount of time; please retry
3. Notes error: The operation is stopped by user request
4. Notes error: Unknown path from the node to the destination address
5. Notes error: Operation cannot be performed at the current time - database compaction in progress
6. Notes error: Error validating user's agent execution access
7. Notes error: User name not found in Domino Directory
8. Notes error: No names found to send mail to
9. Notes error: Cant convert Notes Rich Text Message in MIME format
10. Notes error: The document was rejected in accordance with the rules of email
Working with documents:
11. Notes error: The document is already locked by someone else
12. Notes error: Provisional locks on the master lock database are not allowed
13. Notes error: You cannot update or delete the document(s) since you are not listed as an allowable Author for this document - including for locking
14. Notes error: Document has been deleted
15. Notes error: Database already contains a document with this ID (UNID)
16. Notes error: Adding entry will cause text list to exceed 64K. Entry not added
17. Notes error: Cannot store document - database has too many unique field names. Please set the 'Allow more fields in database' option or ask your administrator to compact the database.
I think that this is not an exhaustive list...
When several of these errors occur in the same code, then the analysis turns to hell. You have to compare the texts of errors that bad, because users/organizations can be installed Notes Clients/Domino Servers in different localizations...
I ask for each error to allocate a unique number.