Error running v15 DB Upgrade Script - TessituraSQLServices

We are in the process of upgrading one of our existing test environments from 14.1.6 to 15.0.5.  However during the upgrade Tessitura DB script. we are receiving an error:

Msg 6528, Level 16, State 1, Server DEVTESSV15, Procedure TXP_CLR_DIAGNOSTICS, Line 1
     [exec] Assembly 'TessituraSQLServices' was not found in the SQL catalog of database 'impresario'.
BUILD FAILED

Has anyone experienced this before?  The environment was working fine prior to attempting the upgrade.

Thanks

Scott