how to read a core file in unix. (the file name is "core")

Core files are memory dumps that are examined using debugger ... Core files are generated typically at the time of crash and they are used for debugging process state at the time of crash
e.g.
gdb corefile executablefile

Doing

file core

will tell you which process dumped core.

In Solaris, you can analyse a core file with

dbx
mdb
pstack

You won't have gdb on your system, unless you've installed the GNU debugger.

thanks. I am unable to use gdb. Is there any useful tip on how to use mdb ?

To get a quick glance at the file use:

#>strings core | more

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Canceling account is not a valid reason for self accept. What was the solution you reached?