Runtime Error 1004 is something that affects Excel, specifically, and it's not exactly a PDF2XL problem. We try to develop the software to be able to circumvent the issue, but we are not able to correct it100% of the time.
*The following information has been made available by Microsoft.
Possible reasons for receiving this error:
When filtered data is copied and then pasted into MS Office Excel workbook
A range value is set programmatically with a collection of large string
Application or object defined error
Conflict with other programs while opening VBA Excel file
Corrupt desktop icon for MS Excel
If all the above steps fail, you can try reinstalling your Excel program.
Read more or access Microsoft support at: http://support.microsoft.com/kb/832166