My tables are not working any more please help..

[Elahe Shafie]

Hi Friends,
Today I was working on back up the tables in MySQL and first I lock the tables and...like bellow:
mysql> LOCK TABLES bug READ;
mysql> LOCK TABLES user;
mysql> FLUSH TABLES;
mysql> UNLOCK TABLES;
This exactly what I did but my tables is not workinh any more I don't know what I did PLEASE help me
Many Thanks,
Elahe