Fixing Javascript Error: Class not registered in Internet Explorer

We were working on an online billing application for a small charity firm when we came upon this problem. The application was developed and tested under Firefox. However we got the error when we tested it on Internet Explorer 6 (6.0.2900.2180). There was a simple window.open javascript call to open a popup window. The window was opening fine but it remained blank and the parent window showed the javascript error

Error: Class not registered.

The line number was pointing to the line with the window.open code. We tried uninstalling and reinstalling Internet Explorer but to no avail.

After some searching we came upon this thread in a forum with the solution to the Class not registered error.
http://www.webdeveloper.com/forum/archive/index.php/t-58228.html
The solution was simple just re-register the IE dlls using the following commands in a batch file. You could also copy and paste directly into a command prompt to get the same result.

regsvr32 c:\windows\system32\urlmon.dll
regsvr32 c:\windows\system32\actxprxy.dll
regsvr32 c:\windows\system32\shdocvw.dll
regsvr32 c:\windows\system32\mshtml.dll
regsvr32 c:\windows\system32\browseui.dll
regsvr32 c:\windows\system32\jscript.dll
regsvr32 c:\windows\system32\vbscript.dll
regsvr32 c:\windows\system32\oleaut32.dll