Index: code/sys/sys_main.c
===================================================================
--- code/sys/sys_main.c	(revision 1489)
+++ code/sys/sys_main.c	(working copy)
@@ -541,7 +541,15 @@
 	// Concatenate the command line for passing to Com_Init
 	for( i = 1; i < argc; i++ )
 	{
+		qboolean containsSpaces = strchr(argv[i], ' ') != NULL;
+		if (containsSpaces)
+			Q_strcat( commandLine, sizeof( commandLine ), "\"" );
+
 		Q_strcat( commandLine, sizeof( commandLine ), argv[ i ] );
+
+		if (containsSpaces)
+			Q_strcat( commandLine, sizeof( commandLine ), "\"" );
+
 		Q_strcat( commandLine, sizeof( commandLine ), " " );
 	}