CCL:G: ONIOM calculation errors. Help!

 Sent to CCL by: "Yuanyuan  Cui" [wicky.cc*gmail.com]
 I'm doing a 2-layer ONIOM calculation. My ligand are two Zinc ions are set to
 the high layer (rhf/6-31g*) and 16 residues from the protein active site around
 this ligand are set to low layer (i tried amber and am1). I deleted the backbone
 of the residues and added H for the valence. But I met several problems with
 this setting.
 1. I used gaussview3 to prepare the input file for ONIOM. It works ok for the
 high layer, but after I set the charge for the low layer to be -2 (two Asp in
 the low layer), it can't let me to set the multiplicity to be 1 (it only
 provides the options of 2, 4, etc). This happens for both amber and am1. If I
 change the multiplicity to be 1 manually in the gaussian input file it
 generated, it will complain can't combine multiplicity 1 with 258 electrons.
 What could be the problem of this?
 2. When I tried to run with multiplicity to be 2 and use am1 for the low layer,
 it ran for about one day and got error complaining "unable to achieve
 self-consistence". I have used SCF(maxcycle=2000). How can I solve this
 problem?
 3. When I tried to run low layer using amber, it keeps complaining "Missing
 atomic parameters for atom 204". How can I know what parameters it missing
 and how can I add those parameters?
 I really appreciate your help!
 Yuanyuan Cui
 wicky.cc|-|gmail.com
 Cambridge, MA
 USA