Monitor error 3

I have also Added the following reserve lines
8H-0BH, 0ACH-0AFH

Those lines are supposed to be added not to the monitor's linker configuration, but to the application's. They prevent the application from using these memory areas because the monitor uses them as interrupt vectors. The monitor will not overwrite them during download anyway, so the RESERVE directive only prevents the warning.
By the way, the interrupt vector table MUST be in RAM, otherwise the monitor in bootstrap mode simply will not work. You have to change your boards memory layout - the RAM area must start at 0. You will have to modify ADDRSELx registers.
There may be other points that you are missing. Read Keil's documentation on Monitor166: Keil\C166\hlp\GS166.PDF, Keil\C166\MONITOR\README.TXT. Look through articles on Monitor166 in Keil's Support Knowledgebase:
http://www.keil.com/support/index.asp?product=MON166&title=MON166%20Target%20Monitor

It took me a while to get the monitor working first time: simply finding the working configuration can be very tricky.
Regards,
- Mike

I have also Added the following reserve lines
8H-0BH, 0ACH-0AFH

Those lines are supposed to be added not to the monitor's linker configuration, but to the application's. They prevent the application from using these memory areas because the monitor uses them as interrupt vectors. The monitor will not overwrite them during download anyway, so the RESERVE directive only prevents the warning.
By the way, the interrupt vector table MUST be in RAM, otherwise the monitor in bootstrap mode simply will not work. You have to change your boards memory layout - the RAM area must start at 0. You will have to modify ADDRSELx registers.
There may be other points that you are missing. Read Keil's documentation on Monitor166: Keil\C166\hlp\GS166.PDF, Keil\C166\MONITOR\README.TXT. Look through articles on Monitor166 in Keil's Support Knowledgebase:
http://www.keil.com/support/index.asp?product=MON166&title=MON166%20Target%20Monitor

It took me a while to get the monitor working first time: simply finding the working configuration can be very tricky.
Regards,
- Mike

We have just had the same problem, but have tracked it down.

We had defined a C-accessible variable in the mm310.a66 startup file, using the DW statement. DW creates an initialised variable - the monitor initialises it not the application. However, the monitor and application have different memory maps. The monitor was reading the location of the variable from the uploaded .h86 file, but whereas the monitor considered that location to be in external flash (and couldn't write there, hence the error), our application configures that to be in external SRAM.

The solution was to use the DS statement instead of DW - this is an uninitialised variable so the monitor never tries to write to the external flash.