Are all switches in the VTP domain running the same version of VTP?
Catalyst 1900 and 2820 switches only support VTP version 1. Make sure that any Catalyst 5000-series switches in the VTP domain are also running VTP version 1. Standardize the VTP version running on all switches in the VTP domain. Catalyst 1900 and 2820 switches only support VTP version 1. Make sure that any other switches in the VTP domain are also running VTP version 1.