Sleep when still in use

Question

I am running on a MAC Pro 4,1 2.66 GHz dual quad core with 8GB Ram, Mac OS X 10.7.3. 
About once an hour my Mac goes to sleep while I am actively using it.  Once it goes to sleep I can wake it back up by clicking the mouse.  Today I was using Logmein to remote into my work and it went to sleep 3 times.  This also caused the logmein session to disconnect.  I check my power/sleep settings and everything looks normal (the same as they have always been).  I remote in a lot and normally use my MAC for many hours at a time and I have not had this happen until today.
Energy Saver:
Computer sleep is set to one notch below the "1 hr" mark
Display sleep is set to one notch below the "1 hr" mark
The Energy Saver checked items are:
Put the hard disk(s) to sleep when possible
Wake for Ethernet network access
Allow power button to put the computer to sleep
System Version:          Mac OS X 10.7.3 (11D50b)
Hardware Overview
  Model Name:          Mac Pro
  Model Identifier:          MacPro4,1
  Processor Name:          Quad-Core Intel Xeon
  Processor Speed:          2.66 GHz
  Number of Processors:          2
  Total Number of Cores:          8
  L2 Cache (per Core):          256 KB
  L3 Cache (per Processor):          8 MB
  Memory:          8 GB
  Processor Interconnect Speed:          6.4 GT/s
  Boot ROM Version:          MP41.0081.B08
  SMC Version (system):          1.39f5
  SMC Version (processor tray):          1.39f5
  Serial Number (system):          H00243SD20H
  Serial Number (processor tray):          C07019501P3DCVHAW
Thank you for any help you can offer.

Answer 1

Intel-based Macs: Resetting the System Management Controller (SMC)