Dear Glen
I am assuming you are using Dako buffers and the autostainer for Herceptest, 
while we do not have herceptest, I am wondering if your problem is temp or 
Ph, could your Di water have contamination? It strikes me as odd that the 
buffer when warm would not enhance staining. I only ask this because we have 
seen variances in our lab with water contamination??????                   
Dana