Please check the merge fields on the letter object.

• The most common issue with the statement generation is merge fields are not valid.
• Use the letter builder/email templates to add fields to the merge text.

If you've added custom fields to the field sets, try removing those and testing again.  Please note, for field sets, you can only add fields from that Object and NOT related object (e.g contact FirstName).

On the statement campaign, related list campaign members.

• Click into a campaign member - press the annual statement button there.
• This might show an individual statement PDF generation error message that might be helpful.

Another item to try is removing most of the text from the receipt letter body and retrying. NOTE: please do not remove all text, but leave a little - e.g "Hi Donor". If the removing of text works, use the Letter Builder to add fields back in.