I found that under PHP 4.0.4pl1 / IIS 4 / CGI, odbc_pconnect problems occur under normal odbc_connect.

Example:

function a() {
	$connect = odbc_connect(DB_DSN,DB_USERNAME,DB_PASSWORD);
	$query = "SELECT a FROM e";
	$result = odbc_exec($connect, $query);
	while(odbc_fetch_row($result)){
		print odbc_result($result, 1);
	} // while

	odbc_close($connect);

	return true;
} // a

function b() {
	$connect = odbc_connect(DB_DSN,DB_USERNAME,DB_PASSWORD);
	$query = "SELECT b FROM e";
	$result = odbc_exec($connect, $query);
	while(odbc_fetch_row($result)){
		if (odbc_result($result, 1) == 'z') {
			a();
		} // if
		print odbc_result($result, 1);
	} // while

	odbc_close($connect);

	return true;
} // b

A call to function "b" will cause a "Warning: 2 is not a valid ODBC result resource" for "odbc_fetch_row" *if* odbc_result($result, 1) == 'z' was true and, as a result, function "a" was called.  This seems like a bug.  Like the "odbc_close" in function "a" is affecting the condition of the value of "$result" in function "b".  Surely PHP allows multple connections to an ODBC data source, right?!