Resolution:
Microsoft has moved the logical disk information from performance to the MMC under the storage section in Windows 2000.  Hence LogicalDisk method is not available on Windows 2000 under the NT HMA performance microagent.  As a workaround, there is a System Event that is posted when the disk gets low (Note: The default Windows 2000 hawk rulebase has a rule that monitors the System Events).
Taken from TIBCO/Hawk release notes:
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To obtain performance counter data for
logical drives or storage volumes, you must
type diskperf -yv at the command
prompt, and then press the Enter key. The
system must be re-booted for this change to
take effect. For complete details see
Microsoft article Q253251.
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I do not see performance:LogicalDisk method in my Hawk 3.1 HMA on Windows 2000? Does it exist?