Dear dingus and tachyon, (and anyone else whose listening),
Thanks for taking the trouble to respond and for pointing out how the regex expertise we lean form perl can easily be taken to JavaScript. ( I guess the same is true now for Java and C#).
Anyways, my problem remains, perhaps because I have not explained the problem properly - the template codes can expand to any arbitrary string - so for example the template could expand to a string like:
Larry said "Let there be light"; Bill swallowed hard.
This gives a runtime error on my IE5.5 with JS debugging turned on. e.g.

var problem = "Larry said "Let there be light"; Bill swallowed hard";
[download]

Do you get my problem? Maybe it's impossible without opening the black-box.
Thanks again for any suggestions, guys.
perlcgi