TC_FF: evalXPath will not evaluate variable inside of for loop

Suppose I have an XPath like this:

evalXPath("(//a[text()=\"2\"])[1]");

Success! Object found.
 

Now suppose I variablize it:

var q=2;
evalXPath("(//a[text()=\""+q+"\"])[1]");

Success! Object found.

Now suppose I wrap it in a for loop:

For (var q=1; q<8; q++)
evalXPath("(//a[text()=\""+q+"\"])[1]");

FAIL

Why?