Help with AC construct fail

Hello,

    I am new to MS and Amorphous Cell. I am trying to create a polymer configuration for further molecular dynamics study. The error I get is "AmorphousCellConstruct failed because the constituent molecules contain atoms with unknown forcefield atom types."

Here are the steps I went through (for creating polystyrene configuration)

1) Create homopolymer in Build > Build Polymers > Homopolymer > create a 4 chain polystyrene molecule

   See step 1 snapshot in attached word doc.

2) Modules > Discover setup > Calculate forcefield type

See step 2 snapshot in attached word doc.

3) I can see the assigned forcefield type when I select a particular atom

See step 3 snapshot

4) Modules > Amorphous Cell Construction > add the polystyrene just created > click construct -- get error shown in snapshot 4.

Get following error "AmorphousCellConstruct failed because the constituent molecules  contain atoms with unknown forcefield atom types."

Please see attached files and snapshots in word doc.

I am using MS 3.2 on Windows XP machine.

Any help regarding this is greatly appreciated