Creation of Donations is not possible

When creating a new donation record I see this error message:

2: SQL error: 'Incorrect integer value: '' for column t3o-prod.tx_t3odonation_domain_model_donation.feuser at row 1' (tx_t3odonation_domain_model_donation:NEW5fbe236047bae651546058)

Can you check this?

Thanks!

Olivier