Backup Failed At 57% Several Times With Error Code 0x81000039

I have been trying to do a backup with system image since Jan 15th on an Iomega 1TB external HD. Tried about 7 times and each time the backup fails at 57%. The message I receive with each failure is as follows- "Windows backup encountered an error when accessing the remote shared file. The semaphore timeout period has expired. Details: Error code 0x81000039" I chatted with a tech from my external HD manufacturer and he finally told me that the problem was with my OS and settings. I tried doing a backup on a different external HD and still failed at 57%. I have no idea which remote shared file the program is looking for. I have a home network and one other computer. That laptop was turned on so if it was looking for a file there it was available. The tech suggested that I turn off my antivirus and firewall and if I was concerned about intrusion to disconnect from the internet. Did that and the backup still failed. I have the same setup on desktop and laptop Windows 7 SP!, Vipre antivirus and firewall, and I was able to do a backup on my laptop. Another slight problem is when I have the Iomega HD running my computer will freeze randomly. For this reason I don't keep it on all the time but just turn on for a monthly backup. I was able to do one initial backup on that HD with no problem. I was told to look at the windows backup log files but they all have a .etl extension and I do not know how to open them to see if the logs give me any idea what file it is hanging up on.