[jQuery] slideDown problem in IE6 and IE7

[jQuery] slideDown problem in IE6 and IE7


Very new to this but really puzzled by an error in IE6 and IE7.
I'm using the fx slideDown effect and it is giving me an 'Invalid
Argument' error - Fine in FF and Safari.
I've got so far with this project I can't believe I'm getting stuck on
this.
Many thanks