Cannot copy file msg accessing files with local language characters in name thru a LAN

Scenario:
My PC: WinXP - Brasilian Portuguese
Wife's PC: WinMe - English
LAN Connection.
All permissions given.

All works fine, except...

I (XP-Portuguese) cannot copy (or view) any files from my wife's hard
drives that contain *some* of the letters in portuguese that have
accents on them - not ALL accented letters, just some.

On my wife's WinMe-English the file names are fine - with their
correct accents in the names - even though her PC is WinMe-English -
albeit with a brasilian keyboard defined.

However in my WinXP-Portuguese (also brasilian keyboard defined) when
I "look" at the files in Windows Explorer thru the LAN the names
appear with underscore characters in the place of some of the accented
characters

Examples:

BAD - can't open them across the network:

Exportaç_es brasileiras 2005.doc - should be an õ
Histórico Inflaç_o.doc - should be an ã, but note that the ó is OK

õ = Alt + 0245 - BAD
ã = Alt+ 0227 - BAD

ó = Alt + 0243 - OK

GOOD- can open them across the network:

BCB - Taxas de Câmbio.doc
Boleto de Cobrança Bancária.doc

â = Alt + 0226 - OK
á = Alt + 0225 - OK


The error message that I receive when I try to copy a BAD file is:

"Erro ao copiar arquivo ou pasta"
"Não é possÃ*vel copiar arquivo. Não é possÃ*vel ler o arquivo ou disco
de origem."

Which translates as:
"Error while copying file or folder."
"It is not possible to copy the file. It is not possible to read the
source file or disk".

If I try to open a BAD file (in Word, for example) I receive the
message:

"Não é possÃ*vel encontrar este arquivo."
"Verifique se o caminho e o nome do arquivo estão corretos."

Which translates as:
"It is not possible to find this file"
"Check that the path and the name of the file are correct"


Any ideas why?

Any idea how to fix it?

--
Perplexed Paulo