I was following this upgrade path http://www.dnnsoftware.com/wiki/Page/Suggested_Up... and have taken a 5.1.2 install all the way to 6.2.8. Now during the upgrade to 7.2.1, the process is hanging at 5%. Below is the end of the upgrade log file.  

I've tried uninstalling third party modules before the upgrade but am not sure where to go from here.  Would anyone point me in the right direction to resolve the issue?

02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade Start AddAdminPage:Advanced Settings
02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade Start AddPagePermission:View
02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade Start AddPagePermission:Edit
02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade Start AddPage:Advanced Settings
02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade Start AddModuleToPage:191
02/17/2014 18:04:27 [INFO] DotNetNuke.Services.Upgrade.Upgrade End AddModuleToPage:191
02/17/2014 18:04:27 [ERROR] DotNetNuke.Services.Upgrade.Upgrade Error: Object reference not set to an instance of an object. at DotNetNuke.Services.Upgrade.Upgrade.ConvertCoreNotificationTypeActionsFor700()
at DotNetNuke.Services.Upgrade.Upgrade.UpgradeToVersion700()
at DotNetNuke.Services.Upgrade.Upgrade.UpgradeApplication(String providerPath, Version version, Boolean writeFeedback)