[Help-glpk] Having trouble specifying a constraint: syntax error in literal set

[joel mortyn]

Hello,

I'm quite new to GLPK and am having difficulty specifying a constraint.  I am modelling production at a furniture plant.  The following constraint is trying to constrain the quantity (Q) of products (p) entering the plant each day (d).  In order for products to enter the plant, it must be set up in a compatible campaign mode (c) which consumes that product {(c,p) in CampProd}.  B[c,d] is a binary variable that specifies whether a campaign will be run on a given day.

The constraint produces a "syntax error in literal set" message:

s.t. quant_consumed{(p,d) in ProdDay}: Q[p,d] <= 9999999 * sum{c in Campaigns: (c,p) in CampProd} B[c,d];

Any help would be much appreciated.