well, yes, if the page is using the gid query string, that is the one you will need to use in the update record behavior.
your sample code at the begining used "id" that is why I used that in the instructions:
$countViews->setSQL("UPDATE wm_inventory SET viewCount = viewCount + 1 WHERE id = {GET.id}");
to trouble shoot the problem, find:
$MM_editCmd = mysql_query($WA_Sql, $WA_connection) or die(mysql_error());
and change it to:
die($WA_Sql);
$MM_editCmd = mysql_query($WA_Sql, $WA_connection) or die(mysql_error());
this will write the update SQL to the screen.
try using this sql directly on the database in PHPMyAdmin or some other MySQL GUI tool.