Is there somewhere (either on here or within the database) that you can see a full list of error codes and what they relate to.
24411 - Worklist item could not be opened (item already assigned)
26031 - Worklist item has been allocated
I think it would be useful to help provide more user-friendly errors to end users.
I'm not quite sure if this is possible out of the box. Perhaps, a place to start is the K2 Hostserver log.
K2 Host Server logging
K2 Auditing and Logging in K2 Five and K2 Platform Classic