there was an error opening this document. The file is damaged and could not be repaired

We are using SQR (Oracle tool) to generate PDF documents for our clients. When we do a bulk generation some of the documents get corrupted with and shows error message as  "there was an error opening this document. The file is damaged and could not be repaired". We are using Adobe XI version 11.0.19

this is happening in our Production so any help is highly appreciated.