We have users experiencing the this issue ONLY if they compose email in new windows:

When they attempt to attach email, the attach email windows show blank. When view message button is clicked. A error message shows:

Unable to parse the search query.
msg: Couldn't parse query:
method: [unknown]
detail: soap:Sender
data: [object Object]
trace: btpool0-86363://mail.domain.com/service/soap/SearchRequest:1346752031793:c570b52ab3cf3512
request: user@domain.com

However, if there is already an attachment in the email, the attach email windows will not have this problem. This happen in IE 8 and Firefox 14.