diff --git a/lcl.c b/lcl.c
index 3f90dc7..effcbb0 100644
--- a/lcl.c
+++ b/lcl.c
@@ -24,15 +24,15 @@ static void
 fmesg(lua_State *L, FILE* f, int shift)
 {
 	int paramc, i;
-	const char *progname; /* argv[0] */
+	char *progname; /* argv[0] */
 
 	paramc = lua_gettop(L); /* get parameter count */
 
 	lua_geti(L, 1 + shift, 0); /* get index 0 of table at index 1 (argv) */
 	if (lua_type(L, -1) != LUA_TSTRING) { /* if argv[0] is not a string... */
-		luaL_error(L, "invalid argument table passed (must have an string in index [0])");
+		luaL_argerror(L, 1, "must have a string in index 0)");
 	}
-	progname = lua_tostring(L, -1); /* set progname to argv[0] */
+	progname = (char *)lua_tostring(L, -1); /* set progname to argv[0] */
 
 	/* format using string.format */
 	lua_getglobal(L, "string");
diff --git a/lfile.c b/lfile.c
index 5dfbf74..639d6b3 100644
--- a/lfile.c
+++ b/lfile.c
@@ -38,10 +38,10 @@
 static int
 file_basename(lua_State *L)
 {
-	const char *path; /* parameter 1 (string) */
 	const char *ret;
+	char *path; /* parameter 1 (string) */
 
-	path = luaL_checkstring(L, 1);
+	path = strndup(luaL_checkstring(L, 1), lua_rawlen(L, 1));
 	ret  = basename(path);
 
 	if (ret == NULL && errno == ENAMETOOLONG) /* check if path is too long */
@@ -70,10 +70,10 @@ file_basename(lua_State *L)
 static int
 file_dirname(lua_State *L)
 {
-	const char *path; /* parameter 1 (string) */
 	const char *ret;
+	char *path; /* parameter 1 (string) */
 
-	path = luaL_checkstring(L, 1);
+	path = strndup(luaL_checkstring(L, 1), lua_rawlen(L, 1));
 	ret  = dirname(path);
 
 	if (ret == NULL && errno == ENAMETOOLONG) /* check if path is too long */