mysqldump not dumping all vibe data

I am backing the vibe database (sitescape) with mysqldump for relocation to another server, however on looking into the file it does not contain all the records. For example ss_principals, the only data record in the backup is for the admin account. There are many other data anomalies, where the various tables are missing data. I have tried doing the backup with Vibe running and not running, with no difference. Also tried a few command line options with mysqldump as well, with no change? Anyone have any ideas?

Thanks in advance,
Mark Currie