In this case consider the following possible solutions:
Your user environment has not been setup correctly to include $DIRSIG_HOME/bin in the list of directories to find executables. Review the steps in the Installation Tutorials section.
The program name may not be named dirsig but rather dirsig-3.6.0 (or appended with the appropriate version number). You can make an alias in your shell to call the longer program name when you type dirsig. Alternately, the person that installed the software can make the set of symbolic links described in the Software Installation section.
If you find that the software is correctly installed and you believe that your executable path is correct, then you should check that you have the appropriate permissions to access the executable files.
This problem indicates that the LD_LIBRARY_PATH was not correctly setup as described in the Installation Tutorials section. This library is distributed with the DIRSIG in the $DIRSIG_HOME/lib directory. Make sure that this library directory appears before all others in the LD_LIBRARY_PATH.
This problem is isolated to the Solaris platform and is related to an operating system library not being installed or up to date. The file /usr/lib/libCstd.so.1 is part of the SUNWlibC package. Talk to your system administrator about having it installed or patched to the most current version. Patches can be downloaded from the SunSolve website: http://sunsolve.sun.com.