diff --git a/aegisub/src/auto4_lua.cpp b/aegisub/src/auto4_lua.cpp
index 4455e2b8a..b6368a332 100644
--- a/aegisub/src/auto4_lua.cpp
+++ b/aegisub/src/auto4_lua.cpp
@@ -436,7 +436,7 @@ namespace Automation4 {
 
 			// load user script
 			if (!LoadFile(L, GetFilename())) {
-				std::string err = str(boost::format("Error loading Lua script \"%s\":\n\n%s") % GetPrettyFilename().string() % get_string_or_default(L, -1));
+				std::string err = str(boost::format("Error loading Lua script \"%s\":\n\n%s") % GetPrettyFilename().string() % get_string_or_default(L, 1));
 				lua_pop(L, 1);
 				throw ScriptLoadError(err);
 			}
@@ -556,7 +556,7 @@ namespace Automation4 {
 
 			try {
 				if (!LoadFile(L, path))
-					return luaL_error(L, "Error loading Lua module \"%s\":\n\n%s", path.string().c_str(), luaL_checkstring(L, -1));
+					return luaL_error(L, "Error loading Lua module \"%s\":\n\n%s", path.string().c_str(), luaL_checkstring(L, 1));
 				break;
 			}
 			catch (agi::fs::FileNotFound const&) {
@@ -595,7 +595,7 @@ namespace Automation4 {
 			return luaL_error(L, "Lua include not found: %s", filename.c_str());
 
 		if (!LoadFile(L, filepath))
-			return luaL_error(L, "Error loading Lua include \"%s\":\n\n%s", filename.c_str(), luaL_checkstring(L, -1));
+			return luaL_error(L, "Error loading Lua include \"%s\":\n\n%s", filename.c_str(), luaL_checkstring(L, 1));
 
 		int pretop = lua_gettop(L) - 1; // don't count the function value itself
 		lua_call(L, 0, LUA_MULTRET);
diff --git a/aegisub/src/auto4_lua_scriptreader.cpp b/aegisub/src/auto4_lua_scriptreader.cpp
index a5e92074a..58676bdab 100644
--- a/aegisub/src/auto4_lua_scriptreader.cpp
+++ b/aegisub/src/auto4_lua_scriptreader.cpp
@@ -58,6 +58,16 @@ namespace Automation4 {
 			return false; // Leaves error message on stack
 		lua_pushlstring(L, &buff[0], buff.size());
 		lua_pushstring(L, filename.string().c_str());
-		return lua_pcall(L, 2, 1, 0) == 0; // Leaves script or error message on stack
+		if (lua_pcall(L, 2, 2, 0))
+			return false; // Leaves error message on stack
+
+		// loadstring returns nil, error on error or a function on success
+		if (lua_isnil(L, 1)) {
+			lua_remove(L, 1);
+			return false;
+		}
+
+		lua_pop(L, 1); // Remove the extra nil for the stackchecker
+		return true;
 	}
 }