HELP: PleskFatalException when opening a domain!

[Hal9000]

ERROR: PleskFatalException

Unable to create SysUser object: SysUser: unable to select: no such row in the table

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0: /opt/psa/admin/plib/class.DomainControlForm.php:171
DomainControlForm->assign(object of type BsDomain)
1: /opt/psa/admin/htdocs/domains/dom_ctrl.php3:148

This happens when i click on a domain in the plesk domain list. All the other domains work fine, but this one spits out the error. How can i fix it?
Please help!
Hal

 

[Hal9000]

i still have this issue. please help me to fix it! i guess it is a db issue, but i dont know where to check since i have no idea what query it tries to make!
the whole domain is completelly inaccessible in plesk right now!
thanks