This BUG is already mentioned in Pull Requests.
File "/var/www/dev/3data/minemap/map-layer/cgi-bin/tilecache-github/tilecache/TileCache/Client.py", line 117, in seed for y in range(startY, endY, stepY): TypeError: range() integer end argument expected, got float.
It is caused by commit from 2011 where a change in Layer.py was made
x = int(x0)
y = int(y0)
-->
x = round(x0)
y = round(y0)
`
I think better solution then change line #117 in Client.py is to fix Layer.py by
x = int(round(x0))
y = int(round(y0))