How to compile cvixml.fp after modifying cvixml.c

I need to modify the below line in cvixml.c

#define XML_PROC_INSTR_DATA "version=\"1.0\""

to this:

#define XML_PROC_INSTR_DATA "version=\"1.0\"encoding=\"ISO-8859-1\""

After opening the cvixml.fp file and creating a project I can then modify the cvixml.c file.  Then when I try to compile I get a "An unspecified error has occurred, probably due to corrupted data".

How do I fix this?  I just want to have my xml files start with the below tag.

<?xml version="1.0" encoding="ISO-8859-1"?>

If ther is a better solution to do this please let me know.  Thanks.