Newbie ask Swap Value: How much Swap do I have

Unlike some other OSes that implement the obnoxious out of memory killer or equivalent, Solaris doesn't overcommit memory (unless you are using very specific allocation techniques). When regular memory allocations are made, the OS make sure this memory will be available when required (i.e. reservation). The drawback is you need to have enough virtual memory space to store this potentially partially unused memory.

Free RAM is unrelated but it accounts in virtual memory size too.

Have a look at "swap -s" output when the problem occurs.

Note that you can easily increase the swap area by adding swap files or devices.

Turn off swap, or use mlockall() to prevent process memory from being swapped out. There are process and system limits though of how many pages can be locked, which may need to be adjusted for your purposes.