As was already stated, prior to your condescending comment above, that you have memory installed on your system that you cannot access, due to limitations with a 32-bit OS installation.
If you want access to more memory, then upgrade your system to a 64-bit operating system. 8 GB would be a good amount of memory for you - you just need the operating system to be able to access it. so that Sonar can load up what you are asking of it and resolve this issue for you.
If you want to blame the software for your memory problems, when nobody else in this forum is doing so, and then disregard the valid assistance that was provided to you, then by all means, continue to suffer the consequences - as you are. Pissing off people who are responding to your requests for assistance is a quick way to getting no further assistance.
In the meantime, I will go back to running Sonar X2 with 20+ soft synths and ZERO memory issues, happily recording with no memory concerns whatsoever.
Bob Bone