Error installing BES Express

Hi All,
     I have a Customer running SBS 2008. I suggested to them that I was going to install BES Express for them. Over the weekend it seems they got impatient and tried to install it themselves. When it didn't work they tried to uninstall it but it didn't uninstall completely.

Now I can't uninstall it even after restart and it won't install either, it gives this message..

"BlackBerry Enterprise Server for Microsoft Exchange -- Internal Error 2803"

and logs this event.


Log Name:      Application
Source:        MsiInstaller
Date:          9/20/2010 11:15:14 AM
Event ID:      10005
Task Category: None
Level:         Error
Keywords:      Classic
User:          Domain\Admin User
Computer:      Server Name.Domain.local
Description:
Product: BlackBerry Enterprise Server for Microsoft Exchange -- Internal Error 2803.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="MsiInstaller" />
    <EventID Qualifiers="0">10005</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2010-09-20T17:15:14.000Z" />
    <EventRecordID>84017</EventRecordID>
    <Channel>Application</Channel>
    <Computer>Server Name.Domain.local</Computer>
    <Security UserID="S-1-5-21-1028268469-82247639-3956178703-1142" />
  </System>
  <EventData>
    <Data>Product: BlackBerry Enterprise Server for Microsoft Exchange -- Internal Error 2803. </Data>
    <Data>(NULL)</Data>
    <Data>(NULL)</Data>
    <Data>(NULL)</Data>
    <Data>(NULL)</Data>
    <Data>
    </Data>
    <Data>
    </Data>
    <Binary>7B32313741453636372D413231302D344330322D383241302D3546333142414144383941337D</Binary>
  </EventData>
</Event>

Can you please help.