On getting any db error lock wait timeout, com.mysql.jdbc.exceptions.jdbc4.CommunicationsException, the data disappears from the db

Question

i am implementing jpa using toplink, and whenever any sort of error comes in the log file, all db entries after the error DISAPPEAR from the db, all errors are caught in a try, catch statement and sent to an error page, still the data continues to disappear, i call commit() after every transaction, i have not called rollback in the code, nor in mysql. Any help would be appreciated greatly.