Migrate a vBulletin 4 forum to Discourse

Ok… so I got the import script to run, though I get an error importing users.

Any idea how I can get past this?

root@discourse-one-app:/var/www/discourse# su discourse -c 'bundle exec ruby script/import_scripts/vbulletin.rb'
root:password@localhost wants vbulletin
Loading existing groups...
Loading existing users...
Loading existing categories...
Loading existing posts...
Loading existing topics...

importing groups...
       16 / 16 (100.0%)  [126440 items/min]   
importing users
Traceback (most recent call last):
        14: from script/import_scripts/vbulletin.rb:999:in `<main>'
        13: from /var/www/discourse/script/import_scripts/base.rb:47:in `perform'
        12: from script/import_scripts/vbulletin.rb:82:in `execute'
        11: from script/import_scripts/vbulletin.rb:129:in `import_users'
        10: from /var/www/discourse/script/import_scripts/base.rb:907:in `batches'
         9: from /var/www/discourse/script/import_scripts/base.rb:907:in `loop'
         8: from /var/www/discourse/script/import_scripts/base.rb:908:in `block in batches'
         7: from script/import_scripts/vbulletin.rb:152:in `block in import_users'
         6: from /var/www/discourse/script/import_scripts/base.rb:264:in `create_users'
         5: from /var/www/discourse/script/import_scripts/base.rb:264:in `each'
         4: from /var/www/discourse/script/import_scripts/base.rb:265:in `block in create_users'
         3: from script/import_scripts/vbulletin.rb:170:in `block (2 levels) in import_users'
         2: from script/import_scripts/vbulletin.rb:990:in `parse_timestamp'
         1: from /var/www/discourse/vendor/bundle/ruby/2.7.0/gems/tzinfo-2.0.4/lib/tzinfo/timezone.rb:575:in `utc_to_local'
/var/www/discourse/vendor/bundle/ruby/2.7.0/gems/tzinfo-2.0.4/lib/tzinfo/timestamp.rb:136:in `for': Integer values are not supported (ArgumentError)