# 3D-Dart Error for Haddock Input **URL:** \ **Category:** HADDOCK\ **Created:** [April 11, 2025, 6:09pm UTC](https://ask.bioexcel.eu/t/3d-dart-error-for-haddock-input/5595 "2025-04-11T18:09:06Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![nikj26](https://avatars.discourse-cdn.com/v4/letter/n/e36b37/32.png) [@nikj26](https://ask.bioexcel.eu/u/nikj26)\ **Post date:** [April 11, 2025, 6:09pm UTC](https://ask.bioexcel.eu/t/3d-dart-error-for-haddock-input/5595/1 "2025-04-11T18:09:06Z")
Traceback (most recent call last): File “/Users/nikj26/3ddart/3D-DART/New Folder With Items/system/CommandLineParser.py”, line 33, in from DARTserver import WebServer File “/Users/nikj26/3ddart/3D-DART/New Folder With Items/system/DARTserver.py”, line 456 if os.path.isfile(SERVERCOUNTFILE): TabError: inconsistent use of tabs and spaces in indentation Attempt to fix this error by changing from tabs to spaces as was needed to be done on xpath.py and commandlineparser.py has not worked. Any other suggestions on how to fix this would be great. Or alternatively if there is a different way to create a DNA PDB file for input into Haddock3 I would appreciate those suggestions as well. I have a 1500bp sequence I need to make the PDB file with. Thanks! ---
**Author:** ![VGPReys](https://dub1.discourse-cdn.com/flex013/user_avatar/ask.bioexcel.eu/vgpreys/32/960_2.png) [@VGPReys](https://ask.bioexcel.eu/u/VGPReys)\ **Post date:** [April 14, 2025, 1:13pm UTC](https://ask.bioexcel.eu/t/3d-dart-error-for-haddock-input/5595/2 "2025-04-14T13:13:22Z")
Dear Nik, You want to build an ab-initio structural model of a 1500 bp sequence ? I am not an expert in DNA modelling, but I am not sure any tool is able to do it properly. You can always try to use PyMOL for that (try: [Fnab - PyMOLWiki](https://pymolwiki.org/index.php/Fnab)). Did you replace `\t` by ` ` (four spaces) ? Stay tuned, maybe someone else will add some better answer