by Benjamin St.Germain.
The problem is this as referenced in a post above if it's happeneing on every Moodle 1 to Moodle 2 import:
https://tracker.moodle.org/browse/MDL-37879
The work around listed in that tracker will fix it:
file: /moodle/backup/converter/moodle1/lib.php
line 1216
comment out these lines:
if ($sourcefullpath !== clean_param($sourcefullpath, PARAM_PATH))
{ throw new moodle1_convert_exception('file_invalid_path', $sourcefull$ }