Invalid characters and url in email content

Hi

I am having a problem when I the user receives the email.
in ramdom parts of the text in the email content gets replaced by "="
and also the urls are not displaying correctly for example if the url for my logo is /http://www.google.com/images/logo.png in the email I will see something like
/http://www.google.c%3Dom= the urls in my settings are fine. but can't see to find a solution for it
I hope someone might be able to help

I am attaching a screen shot to show you my issue
/http://www.tiikoni.com/tis/view/?id=05395eb

Thanks in advance.