I have been trying to download msn messenger but keep getting the error 1603.  What does it mean?  It was intalled already on this computer and I had it last night but this morning it was gone.  Why?  Also the download goes so far then I get a message that says Unknown/Installer/Assemblies/Global, only they are backslashes. What does this mean?  When I double click on the shortcut on my desktop it says something about parameters?

What is wrong?