See this for a general explanation of the problem:
http://community.skype.com/t5/Windows/Can-t-login-Redirected-to-C-ProgramData-Skype-Apps-login/td-p/...
However, the recent testing has shown that if you have the latest version of Internet Explorer, then the problem can be resolved by appropriate registration of JavaScript components. See this:
http://community.skype.com/t5/Windows/Error-when-logging-ing-Skype/td-p/415047/page/2
Do this in order to test if JavaScript is working with your Internet Explorer:
Open in your Internet Explorer (no other browser but only IE) this page:
http://www.mistered.us/test/alert.shtml
Click on the “Simply Click This Button” button and watch the response.
If you don’t get a positive response, then you will need to perform the following registration procedure:
Go to Windows Start -> All Programs -> Accessories -> Right click on Command Prompt, select 'Run as administrator'.
If your Windows is 32-bit version then do this in the Command Prompt window:
Type: regsvr32 jscript.dll, press Enter
If you have Internet Explorer 9 (IE9) installed, then additionally do this:
Type: regsvr32 jscript9.dll, press Enter
After each Enter you should receive a message saying something like: XXX.dll was successfully registered.
If your Windows is 64-bit version, then you need to ensure that in the Command prompt you are in the C:\Windows\SysWoW64\ directory. If you see that you are in System32 folder then type cd.. (2 dots are important) and then press Enter. Next type cd syswow64. Do the same registration commands as mentioned above.
Reboot your computer.
