the %findcriteria hash is built and sent to the CLI, which is expecting to build it's own find hash from a query string.  As such, the play command fails to parse the search from the player UI.

reported in the thread given above, with a possible fix (works for me, but might be a better way):

--- Slim/Control/Commands.pm.old	2006-11-22 12:51:40.425750000 -0800
+++ Slim/Control/Commands.pm	2006-11-22 12:50:28.253875000 -0800
@@ -2221,8 +2222,12 @@ sub _playlistXtracksCommand_parseSearchT
 		} else {
 
 			if ($key =~ /\.(?:name|title)search$/) {
-
-				$find{$key} = { 'like' => Slim::Utils::Text::searchStringSplit($value) };
+				
+				if (ref $value eq 'HASH') {
+					$find{$key} = $value;
+				} else {
+					$find{$key} = { 'like' => Slim::Utils::Text::searchStringSplit($value) };
+				}
 
 			} else {
 
Search -> all songs is fine from web interface