Can you please ask this question more precisely? Asking for
"guidance" is a bit too vague to expect a helpful answer.

> I am doing some data analysis of XANES as well as EXAFS data using
> data analysis software SIXPack. I am not able to load any data file.

This is confusing. How would you be able to use SIXPack if you are not
able to load any data file?

Is the program not responding at all? Does it crash when trying to
load particular files?? I have no idea.

Again, please ask a specific question (for example: why can I not
open the attached data file with SIXPack?), and give as much relevant
information as you can: what operating system are you using, what you
did (File->Open: did a dialog box open??), what SIXPack "does" (any
error messages, for example), Can Athena open the file, and so on.
We're not there to see what you are (and are not) doing. Please
remember that you are sending this request for help to hundreds of
people hoping that one of them will be kind enough to volunteer to
answer. Being polite is wise, but being clear and to the point is
also important.

Thanks for your suggestions. Actually sometimes we are not able to frame the question correctly, which is also one of the reason of not getting a response.

To be specific, I had already opened these data file in Athena and had done analysis on them. But when I try to open these data files in SIXPack, column assingment is required. First I tried to open the E, mu(E) format text file, SIXPack asks for column assingment, but there is no column for mu(E). Then I tried E, I0, It data format and I checked the respected column, but still not able to plot the data. Each time it is giving some error in data plotting like background error, plotting error. The data is loading but I am not able to plot it. I think now I had made myself clear for getting some response.