I got this error while trying to run psconfig. Tried IISRESET and even rebooting the server but they didn't help. After searching around, found this article - http://www.sharepointgeoff.com/spupdatedconcurrencyexception-fix-when-trying-to-install-june-2011-cu-for-sharepoint-server/
I didnit install the CU but still get this error and the steps mentioned below helped to make sure the psconfig completed successfully.
1. stsadm -o setproperty -pn command-line-upgrade-running -pv No
2. IISReset
3. Restart the Windows SharePoint Timer
4. psconfig –cmd upgrade –inplace b2b –wait –force
