Check to see if the PDF file is damaged.
[read-only property] fileIsDamaged([out, retval] VARIANT_BOOL *damaged)
This property contains true if the PDF file is damaged, meaning that the object structure couldn't be parsed, and required repair.

Xpdf attempts to repair all damaged files. If the repair is unsuccessful, loadFile will return an error. If loadFile succeeds, fileIsDamaged can be used to check whether the file was repaired.

If pdf.fileIsDamaged Then ... End If