Appear to lose connection with the Shared Variable Engine

Question

Have been through the boards, but with no success regarding the specifics of my problem.
I am running a real-time application on a PXI-8108.  The host software is taking care of user interface, etc.  Information exchange is handled using Unbound Network Shared Variables (located on the host, though problems occur no matter where the variables are located).  Everything deploys fine.  Software runs swimmingly.  I have backed off the DAQ/communication processes until the RT cores are at <10% busy.  However, occassionally while running, I get a popup "Waiting for Real-Time Target xxx to respond..."  If this message stays up for long enough, then the target's attempts to read the Shared Variables start erroring out with an error -1950679035.  As the variables have already been deployed and used prior to this instant, I find this curious.  If I filter out the error, eventually the real-time software comes back up and everything progresses as though nothing happened.  However, this is a potential deal-breaker for the users who can be impatient with having to wait a few seconds for the software to respond.
Any idea what is happening?  I'm not pumping huge amounts of data over the network, no threads should be starving.  Kinda confused.
Dan M. 

Answer 1

The shared variables are being used much like how a queue would, directing each loop to perform an action should the host require it.  If no action is required, then the loops default to check their respective bus or DAQ.
Currently, I am running 13 timed loops (whose periods I have extended signficantly during debug to no detrimental effect of my software, but to no improvement in the issue in question):
RS-232/J1708 converter loop (50ms period)
CAN loop (50ms)
DMM loop (250ms)
Oscilloscope loop (250ms)
DAQ loop (50ms, includes 1 AI task, 4 DI tasks, and 6 CTR in tasks)
Switch loop (50ms)
RS-232 loops (50ms for the main, 1 additional loop at 1Hz)
RS-485 loops (50ms for the main, 4 additional loops at 1Hz)
Both cores appear to share the load, usually the aggregate load is under 15%.  When the popup appears telling me that the host is waiting for a reply from the target, the PXI controller monitor output still updates the CPU loads, which do not show anything unusual, such as a spike or a freeze in loading.  The target loading does spike up to about 30% total after the communication is reestablished, but that appears to be the software attempting to "catch up" with the events that occurred during the "black out". 
The error reads like this:
Shared Variable in Main Target Application.vi
This error or warning occurred while reading the following Shared Variable:
\\My Computer\Host-Target Interface\RS-485 Messages to Target    [<--insert other variables here]
\\192.168.1.122\Host-Target Interface\RS-485 Messages to Target
Unable to locate variable in the Shared Variable Engine.  Deployment of this variable may have failed.
Are there any other drivers that would be starving the Shared Variable Engine?  For example, if a VISA or NI-DAQmx driver goes to sleep, could it hold up the SVE?  What execution system are they running under? 
Thanks for your help!
Dan M.