Shawn Steele just posted a blog entry entitled Security patch MS07-040 for .Net 2.0 breaks some culture names for .Net 2.0 on Windows XP/2003/2000.

He includes a table that lists the culture names that have changed:

Old .Net Name   RFC 4646 Name, as patched.
en-CB -> en-029
az-AZ-Latn -> az-Latn-AZ
uz-UZ-Latn -> uz-Latn-UZ
sr-SP-Latn -> sr-Latn-CS
az-AZ-Cyrl -> az-Cyrl-AZ
uz-UZ-Cyrl -> uz-Cyrl-UZ
sr-SP-Cyrl -> sr-Cyrl-CS
bs-BA-Cyrl -> bs-Cyrl-BA
sr-BA-Latn -> sr-Latn-BA
sr-BA-Cyrl -> sr-Cyrl-BA
bs-BA-Latn -> bs-Latn-BA
iu-CA-Latn -> iu-Latn-CA
div-MV -> dv-MV
zh-CHT -> zh-Hant
zh-CHS -> zh-Hans

Check out his blog post for more information on how this change can break applications and for workarounds.  There's also an associated KB article available at http://support.microsoft.com/kb/939949.