I tried to upgrade Moodle to newer versions but run into some issues.When upgrading 1.9.9 to 2.0.4 stuck and continue doesn't work. Please refer to attached file. The error is that the upgrade is trying to create multiple exercise tables and they exist already.
I thin this is your second or more attempt at an upgrade and the first one failed.
You must use your original backup sources to restore to where you were and then try again.