Works great on FF, error in IE

Here's a challenge!

The page: http://kiwinc.itgo.com/mwc/intercitytest.html
The same page without Google Maps - no errors:
http://kiwinc.itgo.com/intercity.html
A test page; same js file and same data - no errors:
http://kiwinc.itgo.com/googlemaps.html

IE 6.0 (Windows) errors with:
Line: 375
Char: 726
Error: Unexpected call to method or property access
Code:0
URL: http://kiwinc.itgo.com/mwc/intercitytest.html

It's doesn't look like the IE aborted error.
It's not maps API javascript embedded in a table.
Works great (no javascript errors) in FF 1.0.7 and Opera 8.0
Works great in IE 6.0 on the test page! (googlemaps.html on the list
above)
Couldn't find a similar problem searching the group...

Neither the HTML, nor intercity.js, nor intercity.xml, nor maps.28.js
go all the way to char 726 at line 375. (Line 375 in my html code is
blank!)

Seems like IE choking on polylines...but where and how...and why?
Conflict between Map API code and Adsense code? But why IE specific?
Hmmm....

What do you suggest?

-Ian