AsyncWB is a nice commodity but it has many bugs. I have made at least one post in the past in where i list some of them. Workench.library is partly responsible for this, so if you install the updated version from here:
http://aminet.net/package/util/sys/OS39_update_patcheshttp://aminet.net/package/util/sys/OS39_update_patches2AsyncWB will behave a little nicer, but it will still give problems and that's why i'm not using it.
As for the exec.library of AOS 3.9, it's actually more stable (but slower) than the 3.1's one. The thing is that it's more picky with badly coded programs. Therefore, i think that you should try to locate these programs and replace them with better ones.
Btw, in some accelerators the exec.library of AOS 3,1 is loaded in the chip-ram and this causes a big performance penalty. You can check this from SysInfo or other system monitors.
About the stability problems that you experience, i recommend to install the mcpramlibpatch command from the MCP archive on Aminet, after setpatch.
