Unrecognized UTF-8 initial byte value 0x91

Greetings,

I migrated our ONE headend to a new machine today. Now several views in Sunstone return errors like

Unexpected error executing code for particular method, detected by Xmlrpc-c method registry code. Method did not fail; rather, it did not complete at all. 1937507-byte supposed UTF-8 string is not valid UTF-8. Unrecognized UTF-8 initial byte value 0x91

I tracked one of these down to one of the records in vm_pool but I can’t see what is wrong with it, it doesn’t have any strange characters in it. There are obviously several more issues because of the missing pieces of the interface. I also dropped the mysql database and re-imported it, being very careful that the character set settings were UTF-8, and ran onedb fsck.

Suggestions & ideas appreciated. Thank you.