[gmx-users] DSSP problem

[Mass]

Dear users;
I am trying to run DSSP and have problem, I typed in terminal
do_dssp -f bLac_orig_md2.trr -s bLac_orig_md2.tpr -sc Secondary_Structure_analysis_original_dss.xvg -ssdump


and got the following error, 

Program do_dssp, VERSION 4.6.3
Source code file: /home/mass/gromacs-4.6.3/src/gmxlib/gmxfio.c, line: 524

Can not open file:
bLac_orig_md2.trr
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors

I can see the file bLac_orig_md2.trr in the directory

any comments?