The full error with debug log settings turned on will be something like:
LIBSTOREDATABASE::LOADDBTOSTORE Error: 318: LS2J Error: Threw java.lang.InternalError [ HANDLEJERROR - line 18] on line 1497 in LOADDBTOSTORE
This is probably a known issue with using Notes 9.0.1 FP3 on the client. There is a bug introduced in the fix pack that affects Build Manager when using the Template Registry. You could test this by trying the promotion from a client running FP2 or lower.
We included a workaround in Build Manager 7.2.6 and onwards, so please download the latest Build Manager templates from our download page.
Please upgrade Build Manager as per How do I upgrade Build Manager?