sometimes while running a shell script we use ksh -c '....script'
what is the significance of ksh -c here ....
what if i run the script only.what is the difference

-C Prevent existing files from being overwritten by
the shell's > redirection operator; the >|
redirection operator will override this
noclobber option for an individual file.

Refer "man ksh" for more info

-c is the parameter to state the location of the shell script to be run.
If there are no other parameters on the line, the -c is assumed.
See the "Invoking ksh" section of "man ksh".

I could not understand the answer.I am running couple of commands through one application.I am gettinng some error when directly using the commands but it gets executed when i am using ksh -c '..my commands...'

And the commands are .... the errors are ... ?

Sorry but that statement is incorrect.

From ksh93 man page

     -c       If  the  -c option is present, then commands are
               read from the first arg.   Any  remaining  argu-
               ments  become  positional parameters starting at
               0.

    -c command-string
        The shell executes the command or commands contained in command-
        string.

-c string
    If the -c flag is present then commands are read from string.

We need to see the script which is failing and to know the default shell.
In the context of running a single script with parameters "ksh -c" and the ksh command prompt are interchangeable. This case must be more complicated.