You need to enter a VAT number or taxpayer reference number to register with the LUCID Packaging Register. 
Please check yourself what national identification number corresponds to the German VAT number or taxpayer reference number. The following information will help you:

• The primary purpose of the VAT number is to regulate cross-border transactions within the EU for value-added tax reasons. In many countries (e.g. in Germany) this number is different from a regular identification or taxpayer reference number. If you do not have a VAT number, please indicate this when registering with the LUCID Packaging Register. You will then be automatically prompted to enter a taxpayer reference number.

• The taxpayer reference number is the number that the tax authority assigns to every taxable natural or legal person. It is uniquely assigned to one single taxable person. Companies generally are assigned a taxpayer reference number that they are required to include in their tax returns and invoices.

Are you sure that neither a VAT number nor a taxpayer reference number is assigned to your company? If that is the case, please enter your personal taxpayer reference number.