Error retrieving the feed XML error at rss graffiti

[fatdr]

Hi everyone,
ı want to use facebook rss graffiti for my facebook page and web, but when i entered my feed url myweb/external.php?type=RSS2 i am taking some errors like this;

Error retrieving the feed
XML error: Invalid character at line 196

if i enter the feed url like this;
myweb/external.php?type=RSS2&forumids=2 there is not problem ,

so when i entered another feed url like this;
myweb/external.php?type=RSS2&forumids=96
i am taking error again : Error retrieving the feed
XML error: Invalid character at line 71, column 43

i can't understand this feed xml error. can you help me?