[gmx-users] error in energy minimzation step

[az kalsom]

hi ,

while ruuning the COMMAND

g_energy -f em.edr -o potential.xvg

and following the tutorial

http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin/gmx-tutorials/lysozyme/05_EM.html

 i am getting the following error


Select the terms you want from the following list by
selecting either (part of) the name or the number or a combination.
End your selection with an empty line or a zero.
-------------------------------------------------------------------
  1  Bond             2  Angle            3  Proper-Dih.      4
Ryckaert-Bell.
  5  LJ-14            6  Coulomb-14       7  LJ-(SR)          8
Coulomb-(SR)
  9  Coul.-recip.    10  Potential       11  Pressure        12
Vir-XX
 13  Vir-XY          14  Vir-XZ          15  Vir-YX          16
Vir-YY
 17  Vir-YZ          18  Vir-ZX          19  Vir-ZY          20
Vir-ZZ
 21  Pres-XX         22  Pres-XY         23  Pres-XZ         24
Pres-YX
 25  Pres-YY         26  Pres-YZ         27  Pres-ZX         28
Pres-ZY
 29  Pres-ZZ         30  #Surf*SurfTen   31  Mu-X            32
Mu-Y
 33  Mu-Z            34  T-rest

10 0
Last energy frame read 1545 time 1952.000

Statistics over 1953 steps [ 0.0000 through 1952.0000 ps ], 1 data sets
All statistics are over 1546 points (frames)

Energy                      Average   Err.Est.       RMSD  Tot-Drift
-------------------------------------------------------------------------------
Potential                -2.30149e+06      39000     520034    -251635
(kJ/mol)

You may want to use the -driftcorr flag in order to correct
for spurious drift in the graphs. Note that this is not
a substitute for proper equilibration and sampling!
You should select the temperature in order to obtain fluctuation properties.



please help me , what should i change or do to remove error this error


regards

kalsoom