This issue is similar to the one reported in TECH226794. When editing a detection rule an internal server error is produced. Thus preventing the editing of the rule.
When editing the rule you will see this message: Internal Server Error.
No error is produced in the Altiris log viewer, however, looking in the Windows Event Viewer reveals this:
Event code: 3006
Event message: A parser error has occurred.
Event time: 1/8/2015 8:50:45 AM
Event time (UTC): 1/8/2015 4:50:45 PM
Event ID: 0c38d9b43f834cd8a5a976b96514c165
Event sequence: 1
Event occurrence: 1
Event detail code: 0
Application domain: /LM/W3SVC/1/ROOT/Altiris/PackageRuleManagement-9-130652094450066467
Full Application Virtual Path: /Altiris/PackageRuleManagement
Application Path: E:\Program Files\Altiris\SoftwareManagement\Web\PackageRuleManagement\
Process ID: 6776
Process name: w3wp.exe
Account name: IIS APPPOOL\Classic .NET AppPool
Exception type: HttpException
Exception message: Could not load type 'Altiris.SoftwareManagement.Web.Global'.
Request URL: http://localhost/Altiris/PackageRuleManagement/EditRulePage.aspx?mode=create&managerGuid=4DC4079B-D7A8-4d8d-AE8B-5D6938F137FB
Request path: /Altiris/PackageRuleManagement/EditRulePage.aspx
User host address: ::1
Is authenticated: False
Thread account name:
Thread ID: 48
Thread account name:
Is impersonating: False
at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters)
The files located in the PackageRuleManagement folder do not get upgraded when installing HF5.
Running a repair of Software Management and the Symantec Management Platform are not enough to replace the files. An environment separate from the production environment must be upgraded to HF5 and the files then must be copied from "Program Files/Altiris/SoftwareManagement/Web/PackageRuleManagement" and then placed into the same folder on the defective server. Please back up your current files on the affected server and then delete them from the above location. Also attached are the same files taken from an environment that was upgraded to HF5.