Question : Internet Explorer blocking javascript

I am having issues using a php booking system in internet explorer on windows XP machines. When trying to add or modify reservations, which involves javascript being called, I get the following results:

Win XP (SP3)/IE7 - booking unsuccessful, returns a page with a date of 01/01/1970
Win XP (SP3)/IE8 - booking unsuccessful, returns a page with a date of 01/01/1970
Win XP (SP3)/Firefox - works fine
Win7/IE8 - works fine

I've researched this so far all I know is that it is something to do with IE blocking javascript, though I'm not sure why it works fine in IE on a Windows 7 PC.

I've tried removing anti-virus (mcafee) which didn't help. I've tried adding the site (which is on our intranet) to trusted sites. I've tried lowering privacy and security setting sliders with no effect.

Any ideas how I can get IE to accept the javascript normally? Unfortunately all our staff use Windows XP/IE7 and it's not practical for us to upgrade them all any time soon just to fix this issue.

Answer : Internet Explorer blocking javascript

Question PAQ'd, 500 points refunded, and stored in the solution database.