So, during some off hours, you would want to declare a new schema epoch, which will destroy the schema on all the servers other than the Master of [Root], re-timestamp the Masters schema with the current time, and then distribute that updated schema to the other servers. To do this:
1. Load DSREPAIR -A | Advanced options | Global schema operations | Declare a new epoch. Caution should be taken with this procedure.
2. After a new epoch has been declared on schema, turn on the following DSTRACE screens and look for an ALL PROCESSED = YES for schema sync. SET DSTRACE = +SCHEMA, SET DSTRACE = *SSD, SET DSTRACE = *SSA. If the DSTRACE screen shows an ALL PROCESSED = YES then the schema should be able to be extend successfully for ZENworks for Desktops 4.
After this is complete, you should try to extend the schema with the ZENworks install again.