BT Deployment Woes: Requested registry access is not allowed

Problem:
Uncaught exception (see the 'inner exception' below) has suspended an instance of service 'CreateFacility.CreateFacilityFlow(9dc89e4a-8ade-a4c9-7f35-ca44c0335810)'.
The service instance will remain suspended until administratively resumed or terminated.
If resumed the instance will continue from its last persisted state and may re-throw the same unexpected exception.
InstanceId: c688d7b3-faf0-4b5c-a612-9f2ec41add2f
Shape name:
ShapeId: 00000000-0000-0000-0000-000000000000
Exception thrown from: segment 2, progress 21
Inner exception: Requested registry access is not allowed.

Exception type: SecurityException
Source: mscorlib
Target Site: Void ThrowSecurityException(System.ExceptionResource)
The following is a stack trace that identifies the location where the exception occured

at System.ThrowHelper.ThrowSecurityException(ExceptionResource resource)
at Microsoft.Win32.RegistryKey.OpenSubKey(String name, Boolean writable)
at System.Diagnostics.EventLog.CreateEventSource(EventSourceCreationData sourceData)
at System.Diagnostics.EventLog.VerifyAndCreateSource(String sourceName, String currentMachineName)
at System.Diagnostics.EventLog.WriteEntry(String message, EventLogEntryType type, Int32 eventID, Int16 category, Byte[] rawData)
at System.Diagnostics.EventLog.WriteEntry(String source, String message, EventLogEntryType type, Int32 eventID, Int16 category, Byte[] rawData)
at System.Diagnostics.EventLog.WriteEntry(String source, String message)
at CreateFacility.CreateFacilityFlow.segment2(StopConditions stopOn)
at Microsoft.XLANGs.Core.SegmentScheduler.RunASegment(Segment s, StopConditions stopCond, Exception& exp)



For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Diagnosis:
The application is trying to write to the Windows Event Log but does not have sufficient rights.

Solution:
Gave BT Host Users and BT Isolated Host Users write access to the event log registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog