I guess the hundreds of core files you got is before you set the admin email, don't you?
It should be ok to enabled core dump once the admin email is set, as long as your /tmp has enough space left for maximum 10 core files.
If you do mind, please enable core dump, maybe temporarily, we need to analyze the core or the backtrace to fix the bug.
And please switch to the debug build of lshttpd before enable core dump, you can found the debug build binary in the installation package, lsws-2.1.x/bin/lshttpd.dbg. please copy it over to where lshttpd is installed then change the symbolic link "lshttpd" to "lshttpd.dbg".
Once we identify the location of bug, we will fix it quickly.