This register-messenger-dll.bat file will register DLL files required for Messenger.
To run it simply doubleclick, or click it with right mouse and select Open.

For your safety, it is advised you only download the file from imzers.com
You can always have a look at it's content by opening it with any text editor.

It will execute the following commands:
regsvr32 softpub.dll
regsvr32 Wintrust.dll
regsvr32 Initpki.dll
regsvr32 Dssenh.dll
regsvr32 Rsaenh.dll
Regsvr32 Gpkcsp.dll
Regsvr32 Sccbase.dll
Regsvr32 Slbcsp.dll
Regsvr32 Mssip32.dll
Regsvr32 Cryptdlg.dll

You can also do this by hand. Click Start, and then press Run...
Now type: 'regsvr32 softpub.dll' and click OK or press ENTER. 
Repeat with all other lines as shown above.

Have fun using Messenger!