You can use the SUMIFS function:

=SUMIFS('5-8-13'!$T$2:$T$5000,'5-8-13'!$T$2:$T$5000,"<1E100",'5-8-13'!$E$2:$E$5000,"Americas",'5-8-13'!$H$2:$H$5000,Americas!D$6)