[Serusers] exec_dset() error checking?

The following code fragment causes a SER error rather than returning a detectable failure:

if (!exec_dset("/etc/ser/sipldap")) { sl_send_reply("404", "Not Found"); break; }

Nov 26 15:26:32 ren /usr/sbin/ser[30834]: INFO: SIGCHLD received: we do not worry about grand-children Nov 26 15:26:32 ren /usr/sbin/ser[30834]: ERROR:exec_str: no uri from /etc/ser/sipldap sip:wwww@columbia.edu

The script prints a URI and does exit 0 on success. It prints nothing and does exit 1 on failure. However, this does not appear to be seen as a failure by ser but rather a runtime error. What am I doing wrong?

/a PS: The documentation for exec_dset() misspells it as exec_dst() in http://iptel.org/ser/doc/modules/html/exec.html