[gmx-users] problem with pdb2gmx

[Nizar Masbukhin]

Hi, friends. I’m new to gromacs. I’m trying to learn it based on  tutorial http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin/gmx-tutorials/lysozyme/index.html.
Whenever i input pdb2gmx line, i always get this message:

Using the Oplsaa force field in directory oplsaa.ff

Opening force field file /usr/local/gromacs/share/gromacs/top/oplsaa.ff/aminoacids.r2b
Reading 1AKI.pdb...

-------------------------------------------------------
Program pdb2gmx, VERSION 4.5.5
Source code file: futil.c, line: 491

File input/output error:
1AKI.pdb
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors
------------------------------------------------------- 

What is wrong? can anyone explain?

Thank for your help