How to Output Error Message to page

An "internal server error" means just that. The error occurs at the level of the server, not at the level of code. Unless the code is server-related.

What do the log files coldfusion-out.log, coldfusion-error.log and server.log say? If the error is triggered by server-related code, a try/catch might provide more information:

<cfscript>
	try {
    	// bothersome code
	}
	catch (any e) {
	    writedump(var=e, label="Exception");
	}
</cfscript>