2.5 pounds is quite a bit overwheight. Try going over your building process and accessory list to determine where the extra came from.
You could call around to dealers and distributors to help evaluate your setup and the 'normal' flying weight for what you've got in it.
Is your scale fairly accurate? (All things weighed equally the simplest explanation tends to be the right one.)

Pettit had some good advice too.

Good Luck