Winmail.dat / TNEF Issues 1 user receives, 1 user fails

[Alex Short]

We are having issues with a particular user that never seems to get his
winmail.dat files from a partner.

Here is the strange thing.  Partner emails
user1 at ourcompany.com,user2 at ourcompany.com and TNEF extracts and sends
user1 the word documents within but doesn't send to user2.  In the logs it
just says

--
Aug 13 13:50:55 iomail-gw MailScanner[21126]: Corrupt TNEF winmail.dat
that cannot be analysed in message k7DHonGJ024825
--

Version we are running

--
MailScanner E-Mail Virus Scanner version 4.52.2
--

There is a great deal of correspondance between partner and user1&user2
and this has occured on the last 15 emails (user1 gets, user2 denied)

Please help!