msi: Avoid a null pointer dereference.

dlls/msi/database.c

@@ -778,6 +778,11 @@ static UINT MSI_DatabaseImport(MSIDATABASE *db, LPCWSTR folder, LPCWSTR file)
     lstrcatW( path, file );
 
     data = msi_read_text_archive( path, &len );
+    if (!data)
+    {
+        msi_free(path);
+        return ERROR_FUNCTION_FAILED;
+    }
 
     ptr = data;
     msi_parse_line( &ptr, &columns, &num_columns, &len );

dlls/msi/tests/db.c

@@ -2369,6 +2369,12 @@ static void test_msiimport(void)
     r = MsiOpenDatabaseW(msifileW, MSIDBOPEN_CREATE, &hdb);
     ok(r == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %d\n", r);
 
+    r = MsiDatabaseImportA(hdb, CURR_DIR, NULL);
+    ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_INVALID_PARAMETER, got %d\n", r);
+
+    r = MsiDatabaseImportA(hdb, CURR_DIR, "nonexistent");
+    ok(r == ERROR_FUNCTION_FAILED, "Expected ERROR_FUNCTION_FAILED, got %d\n", r);
+
     r = add_table_to_db(hdb, test_data);
     ok(r == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %d\n", r);