Stop running this script?

Microsoft suggest a solutions here

Create a new DWORD value called "MaxScriptStatements" under HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Styles in register database to set the value to the desired number of script statements or 0xFFFFFFFF to completely avoid the dialog.

control panel/ internet options/ advanced uncheck disable script debugging and check on notification for script error.

If using different browser, similar message may show up like this too.. 

Warning Unresponsive script Firefox

Turn on Javascript console to inspect which javascript failed.
Sometimes old cookies or temporary files can keep returning you to a script error page.
Running Virus scanning to clear some mal-functional left over too.