M *** ERROR => ThrtDatabaseEnvInit: db_init failed (4) [thrtDatabase 48]
M *** ERROR => ThrtDatabaseEnvInit failed (4) [thxxext.c 181]
M *** ERROR => ThCallHooks: event handler ThrtStartup for event CREATE_SHM failed (4) [thSos.c 2081]
If you have cleaned up the shared memory segments before restarting the SAP system manually then most probably the issue could be with the kernel.
Similar issues are mentioned in these SAP notes but on of them is for AIX and you are on Solaris.
1897221 - Work process restarts after you apply kernel patch
1889466 - Memory Management errors on AIX in 7.40 kernel
If possible try with a different patch level of the kernel 740 and see if that helps.
Regards
RB