Writing CSV Rows to a Dataframe : I am using the csv library to read specific rows from several files I have. The problem I am having is saving those rows into a dataframe. I am getting an indexing error that I can't solve.

The current version of the code finds the column names (which is on the third row) and then starts finding the data I need (which starts on the sixth row and continues until it hits a blank row). Finding the column names works fine, but when I try to append the data to it, I get the error:
"InvalidIndexError: Reindexing only valid with uniquely valued Index objects"

The code I currently have is as follows:

        i=0
        import csv
        import pandas as pd
        df = pd.DataFrame()
        with open('C:/Users/sword/Anaconda3/envs/exceltest/RF_SubjP02_Free_STATIC_TR01.csv', 'r') as csvfile:
            csvreader = csv.reader(csvfile, delimiter=',')
            for row in csvreader:
               if csvreader.line_num == 3:  #this is for the column names
                   print(row)
                   df = pd.DataFrame(columns = row)
                   df.columns = row
               if csvreader.line_num >= 6:  #this is for the data
                   if row: #checks for blank row
                       if i<10: #just printing the top ten rows for debugging purposes, theres thousands I need
                           print(i)
                           i+=1
                           df.append(row)  #this is where I get the indexing error
                   else: # breaks out of loop if
                       break
        print(df) #for double checking if it worked