Hello, I am new in PhpED. When I debug the PHP program I see a line of code highlighted in brown color and there is an exclamation mark in the line number gutter just as you would see a red circle and the line is highlighted in red for break points. I was not able to find what the brown highlighed line means. Could you please point me to where these notations are (I was not able to find it in online help). Thanks in advance.

Probably this is because of unresolved breakpoint, in other words there is no code on that line to execute.
FYI: After debug session start all lines, where breakpoint allowed will be marked with blue dots in gutter.

This pages may be useful for you:
http://www.nusphere.com/products/php_debugger.htm
http://www.nusphere.com/kb/technicalfaq/php_breakpoints.htm