xml validation error

[mavdent]

i have a complex xml file, it can't be validated.
to tell my problem i trimmed it like this:
http://trante.heliohost.org/devn/mypage.xml

i tried feedburner to create an rss feed.
but it didn't become successful.
the validation result is as:
http://feedvalidator.org/check.cgi?u...n%2Fmypage.xml

how can i validate this xml and make feedburner use it?
thank you