I examined this file with GSview and GS 8.32 (latest), as
well as importing into Scribus 1.2.1cvs.

Errors from GSview / GS Output:

GSview 4.6 2004-01-11
play_sound: not implemented
debug=0
Unknown in Comments section at line 4:
  %%AI8_CreatorVersion: 10.0
Unknown in Comments section at line 5:
  %AI9_PrintingDataBegin
Unknown in Comments section at line 13:
  %ADOBeginClientInjection: DocumentHeader "AI10"
Unknown in Comments section at line 14:
  %ADOEndClientInjection: DocumentHeader "AI10"
Unknown in Comments section at line 16:
  %%DocumentNeededResources: 
Unknown in Comments section at line 17:
  %%DocumentSuppliedResources: procset Adobe_AGM_Image (1.0 0)
Unknown in Comments section at line 18:
  %%+ procset Adobe_CoolType_Utility_MAKEOCF (1.13 0)
Unknown in Comments section at line 19:
  %%+ procset Adobe_CoolType_Core (2.12 0)
Unknown in Comments section at line 20:
  %%+ procset Adobe_AGM_Core (2.0 0)
Unknown in Comments section at line 21:
  %%+ procset Adobe_AGM_Utils (1.0 0)
Unknown in Comments section at line 22:
  %%DocumentFonts: 
Unknown in Comments section at line 24:
  %%DocumentNeededFeatures: 
Unknown in Comments section at line 25:
  %%DocumentSuppliedFeatures: 
Unknown in Comments section at line 30:
  %AI7_Thumbnail: 128 128 8
Unknown in Prolog section at line 37:
  %%EndComments
Unknown in Prolog section at line 39:
  %%ViewingOrientation: 1 0 0 1
Unknown in Prolog section at line 40:
  %%EndDefaults
Unknown in Prolog section at line 45:
  %%Version: 1.0 0
Unknown in Prolog section at line 46:
  %%Copyright: Copyright (C) 2000-2000 Adobe Systems, Inc. 
All Rights Reserved.
Unknown in Prolog section at line 390:
  %%Version: 2.0 0
Unknown in Prolog section at line 391:
  %%Copyright: Copyright (C) 1997-1999 Adobe Systems, Inc. 
All Rights Reserved.
Unknown in Prolog section at line 2047:
  %%Copyright: Copyright 1997-2001 Adobe Systems
Incorporated.  All Rights Reserved.
Unknown in Prolog section at line 2048:
  %%Version: 2.12 0
Unknown in Prolog section at line 2240:
  %%Copyright: Copyright 1987-2001 Adobe Systems Incorporated.
Unknown in Prolog section at line 2241:
  %%Version: 1.13 0
Unknown in Prolog section at line 2441:
  %%Version: 1.0 0
Unknown in Prolog section at line 2442:
  %%Copyright: Copyright (C) 2000-2000 Adobe Systems, Inc. 
All Rights Reserved.
Unknown in Prolog section at line 2455:
  %%don't initialize AGMIMG_&customcolorimage, it wrecks
havoc in a nested environment
Unknown in Prolog section at line 2456:
  %%AGMIMG_ccimage_exists not {/AGMIMG_&customcolorimage nd} if 
Unknown in Page section at line 3325:
  %%EndPageComments

DSC Warning
At line 4153:
  %%TrailerThe trailer is normally at the end of a document.
This line was found more than 32k bytes from the end
of the file.  Trailers are not usually this long.
It is more likely that another PostScript file has been
included,
without enclosing it in %%BeginDocument / %%EndDocument.

'OK' will assume this is part of an included file.
'Cancel' will assume this is the trailer
Response = Ignore All DSC
AFPL Ghostscript BETA RELEASE 8.32 (2004-10-26)
Copyright (C) 2004 artofcode LLC, Benicia, CA.  All rights
reserved.
This software comes with NO WARRANTY: see the file PUBLIC
for details.
WM_GSTEXTINDEX not implemented
Displaying non DSC file
/home/peter/Documents/testing/test_square.eps
Warning: EPS file must not use /setglobal
Warning: EPS file must not use /setglobal
Warning: EPS file must not use /setglobal
Warning: EPS file must not use /setglobal


Observations:

Scribus imports it perfectly, using GS 8.32.

There is a lot of Adobe AGM (Adobe Graphics) specific code
in the EPS. 

It fails to load at all with 0.40cvs

Bug reporter should be aware, there are multiple options for
EPS export in Illustrator.. Generally back saving to V.7 or
older, results in far more compatible EPS files for usage
with other applications.

Taking the same file, importing to Scribus and exporting
into Inkscape works perfectly.

I'm not sure if we should call this a bug or a file issue
with AI.