Custom Transformer Parameter not being set

I am using FME 2011 and having a problem passing through a calculated expression to a published parameter in a custom transformer.   Here is what i am doing (which is not working).

 

 

in my main workspace i have 2 published parameters that are used to compute a new value (i.e. param1*param2).    I use the parameter fetcher to grab the 2 parameters, and then the expression builder to compute the new attribute.    I then set this to a published parameter in a customer tranformer.  In this custom transformer, this parameter is linked directly to one of the parameters in the Generalizer tranformer.  When i run i get an immediate crash saying that the Generalizer cannot covert a null string.   When i look at in the inspector, i see my new computed value set to @value(newexpressionattribute) when it shoudl have an integer that was computed (i.e. param1*param2).

 

 

I am sure it is something simple.  Any help would be appreciated.