Do you have any variables or field names for used aliases like "lc_product" ?
Anyway, it could be that as soon as you quit Interactivechange local variable lcfilter is no more recognized. Instead of
>SET FILTER TO mytable.myfield = lcfilter
try (assuming lcfilter has character type):
local lccom
lccom="SET FILTER TO mytable.myfield = '+lcfilter +"'"
&lccom



>Using VFP7.
>
>I have a table in my form that I display in a grid. I want to be able to set a filter on the table when a user selects a value from a drop down.
>
>In my drop down Interactivechange I do this:
>
>***
>SELECT mytable
>LOCAL lcfilter
>lcfilter = THISFORM.combo.value
>SET FILTER TO mytable.myfield = lcfilter
>***
>
>When I do this, I keep getting an error "Variable lc_product is not found".
>
>How do you set a filter in a form?
>
>Thanks,
>
>Jerryt