Flash ignoring math - please help!

I know this sounds strange - but that’s what’s been happening to me. I have this simple if(condition >= textfield && condition <= another textfield){ statement that works everywhere except in my movie. I can even create another movie with only that logic and it performs correctly. Can anyone think of a way to get flash to stop ignoring this line …

for(e = 0; e < _global.dates.length-1; e++){
if(_global.dates[e] >= rstart.text && _global.dates[e] <= rend.text){
_root.mc.zdate.text += _global.dates[e] + "

The only other way I can do this is to perform an xpath query on an xml file (which works fine) except that I can’t then perform subsequent searches on nodes in the result (and tracing always shows the xpath conditions and then the string value?).

Any help would be gretly appreciated as I have this project finished by tomorrow.