Error (0): pdf file is damaged - attempting to reconstruct xref table... when using pdf2text.

This error is seen because the PDF file was not fully retrieved, for example:
[http://.../document.pdf] (-8) -
  [*****][1000163 bytes][77618]
  [ext filter: pdf]
   Error (0): PDF file is damaged -
              attempting to reconstruct xref table...
   Error: Top-level pages object is wrong type (null)
   Error: Couldn't read page catalog
  [pdf filter error: target file is empty!]

Only 1MB of the document were retrieved because Alkaline's default MaxSize value is 1 megabyte. To fix the problem, change this value to a higher one in asearch.cnf, for example MaxSize=10MB .