Here are the things to try. I believe this is a repeat email, so if non of this stuff works let me know your status, but only respond to one of the emails.
The first question I have is what is you HP8491B that is your slot 0 controller? Is it an embedded PC, 1394 module, gpib module etc?
As for the memory that you can use in your VXI-MIO-64XE you do need to use a specific kind, and this is specified in the manual. The manual also states what you have to do to properly install it. There are some switches etc that you must set properly. If you don't have the manual, you can download it from our website.
Once the memory is correct you must tell your CVI program to use that memory in addition to setting it up in MAX. The function call that you must make is:
Set_DAQ_Device_Info (1, ND_VXIMIO_SET_ALLOCATE_MODE,ND_VXIMIO_USE_ONBOARD_MEMORY_AI);
This tells NIDAQ to use the 8M of memory that you have installed on the board instead of using the memory on the controller.
As far as the errors that you were getting, if you are still getting those errors after setting the memory up properly and changing your CVI code to use it. We need to know the exact location i.e. the very specific function call where each individual error occurred. I need more information than just low level daq function call or high level function call. I need the specific names of the functions that cause errors and the exact parameters given to these functions which caused the errors.
It seems that you have set up your scan list properly by putting the trigger level first, but have you actually specified that DAQ use analog triggering, and where you specify analog triggering did you tell it the channel to use there as well. You must do this, it will be in one of your AI setup function calls. I don't support daq so I don't know which one.
Finally I would make sure that you have at least NI-VXI 2.1.1 and NI-DAQ 6.9. I don't know if using HP VISA causes some time of conflict I think that NI-VXI installs our VISA, but if you can see your board in test panels and they pass the resource test it should be okay to talk to them with CVI. Can you do a single shot analog acquisition via the test panels in MAX?
Try these things, and get back to us if things still aren't working or you need more information.