After installing NetExpress 5.1 WrapPack 6 (nxp3251060079.exe), applying WrapPack 7 (nxp3251070047.msp) fails with the following error:

"Error 1920. Service EnterpriseLink Loader Service (ELService) failed to start. Verify that you have sufficient privileges to start system services."

For some reason, the Net Express settings got corrupted and need to be repaired.
 
Here is the step to do a repair on Windows 7 and Windows Server 2008:
1. Go to Control Panel > Program and Features
2. Select Micro Focus Net Express 5.1
3. Click on Repair from the tool bar above the column names
4. Click on Yes to allow NXP32MSI to update software
 
Here are the steps to do a repair on older Windows platforms:
1. Go to Control Panel >  Add or Remove Programs
2. Select Micro Focus Net Express 5.1
3. Click on Change
4. Click on Next
5. Select Repair
6. Click on Next
7. Click on Install
 
Once the repair process is completed, WrapPack 7 can be applied without any problem.