Parse a line in XML format

When I try to parse a line in a file in XML format I get an error:

E- *Error* parseString: argument #1 should be either a string or a symbol (type template = "SS") - ("global_min_aper")

The code I am using is:

axlExportXmlDBRecords("./temp_params.txt" nil)
    minWidth_port = infile("./temp_params.txt")
        when( minWidth_port
            while( param_line = gets(param_line minWidth_port)
                    if(rexMatchp("smooth_min_gap" param_line) then
                    println(list("Global aper raw value = " param_line ))
                global_min_aper = nth( 1 parseString(global_min_aper "<>"))
                    println(list("Global aper parsed value = " param_line ))
                        );if
                    );while
            );when
    close( minWidth_port )

This is basically a copy of the code which works for me on a typical report text file .
Can anyone point out what I am missing here?
Thanks.