When you open the Active Directory Sites and Services snap-in, you receive:

The instruction at 0x71d80a80 referenced memory at 0x00000000 The memory could not be read. Click on Ok to Terminate the program.

NOTE: The exception address may be different.

NOTE: Instead of the error message, the program may quit unexpectedly.

This is generally the result of a missing or corrupt set of registry entries.

NOTE: I would export any keys you intend to import so you will have a backup. You may want to check the backup against the import files and merge any differences.

If the HKEY_CLASSES_ROOT\LDAP key is missing or damaged, import:

Windows Registry Editor Version 5.00                              \[HKEY_CLASSES_ROOT\LDAP\]                              @="URL:LDAP Protocol"                              "EditFlags"=hex:02,00,00,00                              "URL Protocol"=""                              \[HKEY_CLASSES_ROOT\LDAP\Clsid\]                              @="\{228D9A81-C302-11cf-9AA4-00AA004A5691\}"                              \[HKEY_CLASSES_ROOT\LDAP\shell\]                              \[HKEY_CLASSES_ROOT\LDAP\shell\open\]                              \[HKEY_CLASSES_ROOT\LDAP\shell\open\command\]                              @="\"D:\\Program Files\\Outlook Express\\wab.exe\" /ldap:%1"
If the HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\} key is missing or damaged, import:

On a Windows 2000 domain controller

Windows Registry Editor Version 5.00                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\] @="ADs LDAP Pathname Descriptor Object"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\InprocServer32\]@="activeds.dll"                              "ThreadingModel"="Both"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\ProgID\] @="Pathname"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\TypeLib\] @="\{97d25db0-0363-11cf-abc4-02608c9e7553\}"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\Version\] @="0.0"

On a Windows 2000 member

Windows Registry Editor Version 5.00                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\] @="ADs Pathname Object"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\InprocServer32\]@="activeds.dll"                              "ThreadingModel"="Both"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\ProgID\] @="Pathname"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\TypeLib\] @="\{97d25db0-0363-11cf-abc4-02608c9e7553\}"                              \[HKEY_CLASSES_ROOT\CLSID\\{080d0d78-f421-11d0-a36e-00c04fb950dc\}\Version\] @="0.0"