[gmx-users] Error in DNA.itp file

[Ayesha Kanwal]

Hi all,
i am preparing system of DNA-protein complex, downloaded it from RCSB website, by using GROMACS-version 4.5.5; force field AMBER03WS with water Model TIP4P (2005). The DNA chain contains DA, DT, DG, DC atom type.
but the problem is that when i use command for energy minimization the following error has occurred. Error shows that problem is in .itp file Dih. types. For protein .itp files,there was no problem. Only DNA .itp files have issue. Its my first time i am preparing this kind of system please let me know how can i resolve this problem and why these errors were generated ? I have searched out previous mail but could not find relevant answer so i am posting it now here. i have attached .mdp file with this e-mail.

checking input for internal consistency...
Generated 2412 of the 2415 non-bonded parameter combinations
Generating 1-4 interactions: fudge = 0.5
Generated 2415 of the 2415 1-4 parameter combinations

ERROR 1 [file dna-his_DNA_chain_I.itp, line 44148]:
  No default Improper Dih. types


ERROR 2 [file dna-his_DNA_chain_J.itp, line 44148]:
  No default Improper Dih. types