ECW wants to be real particular about these so here is what needs to be done.
First, install the label printer via windows as normal.
Open ECW and go to File–> Settings–> Local Settings
Select “Enable Dymo Label Printing”
Add template for “Dymo Printer Template file”
Find that in Program files–> EclinicalWorks –> Dymo templates–> Adress with Barcode (99010).LWL
Click OK
That should do it.