A failure occurred querying the Writer status.

Hi All, So we've had the same backups running for a few months now, then suddenly over the weekend they start to fail with the errors below. These backups include our domain controllers and Intranet, our other seem to be fine. I've gone through a lot of the Symantec knowledge base and have had no success. Things I've tried: (1) Restarting both the backupexec server and file server. (2) Enabling Advanced Open File with forcing it to use Microsoft's Shadow Copy Provider. (3) Ran "vssadmin list writers" which found 0 errors. (4) Manually started the shadow copy service on the client server. V-79-57344-65233 - AOFO: Initialization failure on: "\\192.168.4.98\Shadow?Copy?Components". Advanced Open File Option used: Microsoft Volume Shadow Copy Service (VSS). Snapshot provider error (0xE000FED1): A failure occurred querying the Writer status. Check the Windows Event Viewer for details. Writer Name: Event Logs, Writer ID: {EEE8C692-67ED-4250-8D86-390603070D00}, Last error: The VSS Writer failed. The operation cannot be retried (0x800423f4), State: Failed during prepare snapshot operation (8). The following volumes are dependent on resource: "C:" . The snapshot provider used by VSS for volume C: - Microsoft Software Shadow Copy provider 1.0 (Version 1.0.0.7). V-79-57344-65233 - AOFO: Initialization failure on: "\\192.168.4.98\System?State". Advanced Open File Option used: Microsoft Volume Shadow Copy Service (VSS). Snapshot provider error (0xE000FED1): A failure occurred querying the Writer status. Check the Windows Event Viewer for details. Writer Name: Internet Information Services, Writer ID: {59B1F0CF-90EF-465F-9609-6CA8B2938366}, Last error: The VSS Writer failed, but the operation can be retried (0x800423f3), State: Failed during prepare snapshot operation (8). Writer Name: Registry, Writer ID: {AFBAB4A2-367D-4D15-A586-71DBB18F8485}, Last error: The VSS Writer ran out of memory or resources (0x800423f1), State: Failed during prepare snapshot operation (8). The following volumes are dependent on resource: "C:" . The snapshot provider used by VSS for volume C: - Microsoft Software Shadow Copy provider 1.0 (Version 1.0.0.7). Please let me know if there's any other information I can provide. I'm not really sure what could have changed in our environment that would cause certain backups to fail suddenly.