Microsoft Outlook 2010: Is there a "Subject Equals" rule filter?

Highlight an existing e-mail you want the rule to be based on (one with the subject you want the rule about), then click "Rules" on the "Home" tab. Click Create rule>Advanced, and you should see the option to check subject with your existing subject already added (the second one down in the screenshot).

P.S. You can also edit the text by checking the box, and then clicking the underlined text in the "Edit the rule description" box below. So just edit out the FW: part, it should still work for you since it is not an exact match situation, I believe, rather just must contain that string, so it should pick up both options. If it does not, create one rule for each subject.

Heres your answer, i hope will help:

Apply this rule after the message arrives with Whatever Site Error received in the subject
move It to the Whatever folder
except if the subject containsi
'RE: Whatever Site Error' or 'FW: Whatever Site Error'

this rule is good for automatic mails, but if someone Replay or Forward the mail this rule will not apply, so you wont mistake the automatic mails whit the users mail.

(!) Do not use exception like : except if the subject containsi 'RE' or 'FW' because it wont work in some cases if the subject contain wards whit RE , like (foREver, REceived,...)