Index: mucs.c
===================================================================
--- mucs.c	(revision 17847)
+++ mucs.c	(revision 17848)
@@ -55,9 +55,8 @@
 
 static const char pcb_acts_LoadMucsFrom[] = "LoadMucsFrom(filename)";
 static const char pcb_acth_LoadMucsFrom[] = "Loads the specified mucs routing file.";
-fgw_error_t pcb_act_LoadMucsFrom(fgw_arg_t *ores, int oargc, fgw_arg_t *oargv)
+fgw_error_t pcb_act_LoadMucsFrom(fgw_arg_t *res, int argc, fgw_arg_t *argv)
 {
-	PCB_OLD_ACT_BEGIN;
 	const char *fname = NULL;
 	static char *default_file = NULL;
 	FILE *fi;
@@ -64,20 +63,24 @@
 	int c, c2;
 	pcb_coord_t x1, y1, x2, y2, r;
 	pcb_pstk_t *ps;
-	fname = argc ? argv[0] : 0;
 
+	PCB_ACT_MAY_CONVARG(1, FGW_STR, LoadMucsFrom, fname = argv[1].val.str);
+
 	if (!(pcb_layer_flags(PCB, INDEXOFCURRENT) & PCB_LYT_COPPER)) {
 		pcb_message(PCB_MSG_ERROR, "The currently active layer is not a copper layer.\n");
+		PCB_ACT_IRES(1);
+		return 0;
 	}
 
-
 	if (!fname || !*fname) {
 		fname = pcb_gui->fileselect("Load mucs routing session Resource File...",
 																"Picks a mucs session resource file to load.\n"
 																	"This file could be generated by mucs-pcb\n",
 																default_file, ".l1", "unixplot", HID_FILESELECT_READ);
-		if (fname == NULL)
-			return 1;
+		if (fname == NULL) {
+			PCB_ACT_IRES(1);
+			return 0;
+		}
 		if (default_file != NULL) {
 			free(default_file);
 			default_file = NULL;
@@ -90,7 +93,8 @@
 	fi = pcb_fopen(fname, "r");
 	if (!fi) {
 		pcb_message(PCB_MSG_ERROR, "Can't load mucs unixplot file %s for read\n", fname);
-		return 1;
+		PCB_ACT_IRES(1);
+		return 0;
 	}
 
 	while ((c = getc(fi)) != EOF) {
@@ -146,8 +150,8 @@
 		}
 	}
 	fclose(fi);
+	PCB_ACT_IRES(0);
 	return 0;
-	PCB_OLD_ACT_END;
 }
 
 pcb_action_t mucs_action_list[] = {