SYMEFA.DB-journal on external hard drive error

I have just run my first complete system scan of NIS 2009 after installing and updating it.

All appeared to go well but i had a popup window when i checked my scan had finished.

In my event log there were numerous system errors.

 

This appeared 3 times.

Application popup: Windows - Delayed Write Failed : Windows was unable to save all the data for the file H:\System Volume Information\EfaData\SYMEFA.DB-journal. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere.

 

I also had several instances of:

The system failed to flush data to the transaction log. Corruption may occur.

 

I was not running anything else on my computer or connected to the internet.

The H drive mentioned is my external hard drive which is connected  to my computer via a usb 1.1 port. Could the first error message be explained by the fact that NIS was trying to write something anf it had problems because of the connection possibly being too slow.

I was assuming that the 2nd message is for the same reason and is just generic ?

 

Could somebody advise if this is possible because of NIS 2009 running of is this accidental ?

 

Thanks in advance for any advice.

 Nigel