BSOD after resuming from sleep

Hi recently I've been getting a BSOD after resuming from sleep mode on Vista
Ultimate 32-bit. I cannot actually see the message as it happens before the
logon screen comes up. But I can tell that the system crashes as I open the
crash dump file in WinDbg:

BugCheck 7A, {c044b570, c000009d, 31f4f860, 896ae2f4}
KERNEL_DATA_INPAGE_ERROR

Later in the debug file, it mentions the error code:

ERROR_CODE: (NTSTATUS) 0xc000009d - STATUS_DEVICE_NOT_CONNECTED

It does not always happen. Sometimes the system resumes quickly with no
problems. Is anyone else having this problem?