Assume the csv file is called a.csv, then preprocess it a bit with this command:
<a.csv tr , \\t | tail -n+2 >a.tsv
Now start gnuplot, and enter the following commands:
set timefmt "%m/%d/%Y"
set xdata time
set key outside below
"a.tsv" using 1:4 title "128", \
"a.tsv" using 1:5 title "440", \
"a.tsv" using 1:6 title "1024", \
"a.tsv" using 1:7 title "Mixed"
Feel free to change the commands if you want to change the formatting, or use the set terminal and set output commands to save the plot as an image.
See also Plot a spiral with gnuplot about the general idea of using gnuplot in perl, and Re: Draw chart as an example that uses times as one coordinate.