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There are two steps to the following solution. If the first
To resolve this error, do the following:
1. Make sure the Cisco VPN client installer is closed before you begin.
2. Click Start > All Programs > Accessories
3. Right-click on Command Prompt in the Accessories section of the Start Menu and select Run as Administrator.
4. Type cd C:\Windows\System32 and then press Enter.
5. Type regsvr32 C:\Windows\System32\vbscript.dll and then press Enter.
6. You will receive a message that says, "DLLRegisterServer in C:\Windows\System32\vbscript.dll succeeded." Click OK.
7. Keep the command prompt window open for now.
You can close this window once you're able to install Cisco VPN client. If the steps above did not resolve the error, you will use the command prompt window in the instructions below.
You should now attempt to install Cisco VPN client. If you get the same error as before, proceed with the instructions below.
Second step
Important: These instructions require you to edit the registry. Do not follow these instructions unless you are confident that you know what you're doing. It is recommended that you make a registry backup prior to editing the registry.
1. Click Start and type regedit in the box.
2. Browse to the following location: HKEY_CURRENT_USER\SOFTWARE\Classes\CLSID\
3. Locate and delete the registry key named {B54F3741-5B07-11CF-A4B0-00AA004A55E8}.
We recommend making a backup of this registry key before deleting it.
4. Close the registry editor.
5. Go back to the command prompt window you used in the instructions above.
If you closed this window, follow steps 1 - 4 above to open the command prompt window using the Run as Administrator option and navigate to the C:\Windows\System32 directory.
6. Within the C:\Windows\System32 directory, type regsvr32 C:\Windows\System32\vbscript.dll and then press Enter.
7. You will receive a message that says, "DLLRegisterServer in C:\Windows\System32\vbscript.dll succeeded." Click OK.
8. Close the command prompt window.
You can now install Cisco VPN client.
Source:
http://helpdesk.illinoisstate.edu/kb/1474/Error_Internal_Error_2738_when_installing_Cisco_VPN_client_on_Windows_Vista_or_Windows_7/