Windows Media DRM issue 0xC00D28B7 / NS_E_DRM_RIV_TOO_SMALL

[Iain]

I have some applications out in the field which have been running for
5 years or more. They all run on XP contain WMRM7/WM7 content which
is decrypted as needed. Some time since Friday a number of these
machines have failed to read the content on them with a
NS_S_DRM_RIV_TOO_SMALL error message.

The description for this is

'The license that is associated with an existing piece of content
requires a more recent certificate revocation list (CRL) version that
is not present on the system. Your application can download a more
recent CRL using IWMDRMSecurity::PerformSecurityUpdate.'

It's not clear what, if any difference there is between the machines
that still work and those which do not. My test VM works fine.

It seems possible that it is an issue with the recency of the
individualization, however the only way to re-do the individualization
seems somewhat agressive (delete the DRM folder as a starter - I seem
to recall this would cause catastrophic disaster [OS re-install] in
some versions of the media player, so I'm a bit nervous about that!).

Can anyone throw any light on this one?

(already posted in windowssdk forum - apologies if you see it twice)

Iain