[lazarus] "Ambiguous Units Found" Message

[Kevin Berry]

Hi,

I've just downloaded the latest FPC 1.0.10 and the lazarus source and 
built it successfully.  After running an application that I created (a 
simple button on a single form with a ShowMessage('hello') in the click 
event) I'm getting a dialog with the title:
  Ambiguous units found
and the text:
  There is a FPC unit with the same name:
  "$(LazarusDir)/lcl/forms.pp" form LCL 1.0"

("Cancel" and "Abort" buttons are the two choices on this dialog).

Have I done something wrong?  How should I deal with this conflict?  
Excuse my ignorance I'm a complete newbie to Lazarus (although I've been 
following the mailing list conversation every now and then).

Thanks,
Kevin.