If you have a special configuration in mysqld (no default config) perhaps you will find these two cases of error working with myloader tool:

  1. The first issue looks like a problem with the backup file…… but it is not. Message:
    ** (myloader:42526): CRITICAL **: cannot open file vcadminweb.message.sql.gz (24)

* (myloader:46190): CRITICAL

In my case, I needed to check and to change the open files:

ulimit -n 10000     ... and solved!
  1. The second one looks like a problem accessing to the database…. but it is not. Message:
    **: Error switching to database CMSB076 whilst restoring table multidevicevideo_players

In my case, it was a timewait very low in the mysqld config.

wait_timeout     = 300

solved the issue for me.