There are one or two threads on here about a 'conflict' (for want of a better word) between BB & Hotmail. Also on the Blackberry Support Forums (although some are the same posters). BB/Hotmail users have reported recipients receiving duplicated emails or just a duplication of the signature followed by your </div> tag.
Does the same happen to your emails to her?
How about if she emails herself?
From what I can gather, it only seems to affect later (OS7) BBs. Which Curve / Bold are you each using?
As I don't use Hotmail, I can't recreate the fault but my suspicion is that it's something to do with the difference between text only & html emails. The BB sends messages as encoded text (if you ever view the message source, it's all garbage but it is plain text - no markup). Most PCs & webmail systems are set to send messages as html by default. An html message source actually contains two versions of the message - one in plain text and a second with html headers.
The </div> tag is html code which tells the reader that a section has ended - there are usually dozens of them in a typical html page. The fact that it's being shown on the screen would indicate that the html has been incorrectly generated and the final tag is unnecessary or without an opening tag.
Perhaps the fault is being generated by Hotmail as it tries to convert the encoded plain text email to an html one?
Is there an option inside Hotmail (in a browser rather than on the BB) to use Plain Text only rather than HTML for all emails?