seems to me u got a text value somwhere in ur referenses

if this 1 is ok

=SUMPRODUCT((($M93='2007 Rems Slide Obl'!$C$4:$C$1918)*('Branches 2007
Budget'!$J93='2007 Rems Slide Obl'!$U$4:$U$1918)*('2007 Rems Slide
Obl'!W$4:W$1918)))


then check if

=IF(ISERROR(VLOOKUP($M85,REMS2007!$M$4:$P$1786,4,F
ALSE)),0,VLOOKUP($M85,REMS2007!$M$4:$P$1786,4,FALS E))

returns a numeric value