Exec Function Hangs In Internet Explorer

I am trying to get an exec to work on the following code:
Code:
i=0;
alert("before exec");
while ((result = /\r\n ?w:/g.exec(lines)) != null) { i++; } //Counts number of lyric lines
if (i > 1) lyricRegExp=/\r\n ?w:([^\]*)/ ;
alert("after exec");

If I find more than one occurrence of a line starting with "w:" (or has spaces before the "w"), I will need to change a regular expression used. The exec() runs fine in Firefox but hangs in Internet Explorer. The whole script I'm trying to test is abctst.htm on line 494. If anyone tries to run this click on Submit, my testing code is already filled in. The alerts shown will run first followed by about six more alerts before highlighted code is created in the bottom textarea.