I saw a previous post on this subject and am having the
same problem.  I have a worksheet that contains a list of
filenames that I need to import, format, print, close the
file, and go to the next file and repeat the process.  
What I am actually doing is creating invoices.  Here's the
details:

1) The file to be opened is a tab-delimited file.  I
created a macro in the original filelist worksheet that
grabs the filename from a cell, goes to "Open File", it
imports the file configuring each column the way I want
(I.E. General, Text, etc.).  It then formats each column
so that is autofits, searches for certain keywords that I
want to make bold, change font size, etc.  It then prints
the file, closes it (without saving the changes), grabs
the next filename, and repeats the process.

THE PROBLEM:  The list of files to open is currently
around 205 files, but this will grow.  It gets through
about 100 files then gives me "NOT ENOUGH MEMORY"
or "INVALID PAGE FAULT" errors.  I have increased the
memory from 128MB to 512MB and still have the same problem
so I know its not the memory.  I have noticed 2 different
files that get the "INVALID PAGE FAULT" error.  The 2
files are AGENTMPX.DLL & SSGS1.DRV.

Is there some kind of limitation in Excel as far as
opening and closing tab-delimited files?  Any input would
be greatly appreciated.  Anyone who is willing to give me
some input can call me toll-free at 1-800-582-1173 and
just ask for Tom.  This is a major problem for me, so any
suggestions are very much appreciated.  Thanks!