My Pythonic take on Psexec
Keep your imports grouped. From PEP 8.

Imports should be grouped in the following order: 


  
  standard library imports
  related third party imports
  local application/library specific imports
  




Follow Python's EAFP principle instead of checking if something exists. Plus when it comes to folder creation it will also help you avoid race-condition.

import errno

try:
    os.mkdir(log_path)
except Exception as e:
    if e.errno != errno.EEXIST:
        # If error is something other than file
        # path already exists then handle it here.
        pass




Note my use of except Exception as e here instead of except Exception, e. The latter syntax is deprecated and has been removed in Python 3. Hence go for as based format.



Your try-except block is huge. Cover minimum statements at once, it will help you in narrowing down the actual problem easily and you will be able to show a much better error message to user. Have multiple try-excepts as long as they don't make the code too unreadable.



Instead of dealing with sys.argv you could use the arsparse module to handle command line args in much better way.



error_message = "" statement is not required. You can simply define it wherever you need it instead of defining a default value.



[1::] and [2::] can be simply written as [1:] and [2:] respectively.



The IndexError at the end is redundant because you're already checking for if not [1::] earlier and exiting the script right away, hence you would never hit that exception. Note that slicing never raises IndexError.



call.communicate("Running remote command...") returns both STDOUT and STDIN. You can consider using them separately.

Plus you could also check the status code by doing call.returncode. A non-zero exit code means an error.



log_path = "C:\\Users\\{}\\AppData\\pyshell".format(getpass.getuser())

A hard-coded path is not a good idea. Perhaps ask the user for a path?

You can also get path to user's home directory using os.path.expanduser.

log_path = r"{home}\AppData\pyshell".format(home=os.path.expanduser('~'))

Note that I also added r"" so that we can simply use a single backslash.