Exact reproducing of the crash was not achievable, but one bug was found and fixed in Zabbix sender. This bug is most likely the cause of crash.
Although the bug has been reported on Solaris 10 (Intel), it can occur on other platforms, too. The bug is triggered after sending data to the Zabbix server, if a corrupted server response is received.
Fixed in development branch svn://svn.zabbix.com/branches/dev/ZBX-5741.