I'm getting the same event log entries over and over and can't figure out

A low level indexing operation has failed
Error: a severe error occurred; cannot continue [AV:63]
Index Id: 14EFE7394A7A352449314D97E7AC3C9721110000VAULT

Abnormal error occurred

Error: A low level indexing operation has failed Error: #1 Index Id: #2 [0xc0041c43]
Reference: CAVUpdator/OAVI/o(h)
Index: 14EFE7394A7A352449314D97E7AC3C9721110000VAULT
Info: IndexExists [FileName=G:\Program Files\Enterprise Vault\Indexing\14EFE7394A7A352449314D97E7AC3C97211 10000VAULT\dataset,
dwFileAttributes=20, dwLastError=0] ;
Params (ignored_thresh=1000; chars_before_wildcard=3; unlimited_wild_words=1;
indexformat=-1; cache_threshold=268435456; options=39; charset=1; ntiers=0;

A low level indexing operation has failed
Error: File I/O error (can't create output file or shared memory) [AV:39]
Index Id: 14EFE7394A7A352449314D97E7AC3C9721110000VAULT

Error updating an index.
[Internal reference GISN]
[VaultId = 14EFE7394A7A352449314D97E7AC3C9721110000VAULT]

Could not get the IndexServer sequence number: The Alta Vista index is not
open [0xc0041c64]
Internal reference: GetSequenceNumber
VaultID: 14EFE7394A7A352449314D97E7AC3C9721110000VAULT

I was troubleshooting the exact same problem yesterday on another vault and
the problem went away when I renamed the index directory on my local drive.
directory was recreated when I restarted the index service and everything
appeared normal. This morning
when I checked the server again, I found the indentical problem occuring
with another vault. Any ideas on what I should be looking at?