This is typically not a memory space issue. Here is why: Our ActiveX control uses the same DLL to draw its barcodes, and we do not see any problems given that we have more than one of them at a time. In fact, our webpage uses the same DLL to draw barcodes and it could have potentially thousands of instances existing at one time (depending on how many users were looking at the page).
Make sure that you are trimming the value of the barcode to the returned length.
Make sure that you are trimming the value of the barcode to the returned length.