PDF generation broken?

Oke, so I added the path to my open_basedir setting. Now I also removed my vendor folder and run composer install again. Now I’m getting a huge load of warnings, 872 to be exactly!!! All errors like this:

Warning: Ambiguous class resolution, "AddCustomContactFields" was found in both "/var/www/vhosts/domain.nl/facturen.domain.nl/database/migrations/2017_04_16_101744_add_custom_contact_fields.php" and "/var/www/vhosts/domain.nl/facturen.domain.nl/database/database/migrations/2017_04_16_101744_add_custom_contact_fields.php", the first will be used.
Warning: Ambiguous class resolution, "AddSwapPostalCode" was found in both "/var/www/vhosts/domain.nl/facturen.domain.nl/database/migrations/2015_09_04_080604_add_swap_postal_code.php" and "/var/www/vhosts/domain.nl/facturen.domain.nl/database/database/migrations/2015_09_04_080604_add_swap_postal_code.php", the first will be used.
Warning: Ambiguous class resolution, "AddDanishTranslation" was found in both "/var/www/vhosts/domain.nl/facturen.domain.nl/database/migrations/2014_10_14_225227_add_danish_translation.php" and "/var/www/vhosts/domain.nl/facturen.domain.nl/database/database/migrations/2014_10_14_225227_add_danish_translation.php", the first will be used.
Warning: Ambiguous class resolution, "AddCascaseDrops" was found in both "/var/www/vhosts/domain.nl/facturen.domain.nl/database/migrations/2014_02_13_151500_add_cascase_drops.php" and "/var/www/vhosts/domain.nl/facturen.domain.nl/database/database/migrations/2014_02_13_151500_add_cascase_drops.php", the first will be used.
Warning: Ambiguous class resolution, "AddInvoiceFontSupport" was found in both "/var/www/vhosts/domain.nl/facturen.domain.nl/database/migrations/2016_01_06_153144_add_invoice_font_support.php" and "/var/www/vhosts/domain.nl/facturen.domain.nl/database/database/migrations/2016_01_06_153144_add_invoice_font_support.php", the first will be used.

Running /update is going fine by te way. But when I now go to an invoice, I’m getting an error.

(1/1) FatalThrowableError
Call to undefined method App\Ninja\Presenters\AccountPresenter::customLabel()