pt-diskstats errors

I am using following command.
bash pt-diskstats -d fioa

in output I get:

grep: /tmp/diskstats-samples: No such file or directory
pt-diskstats: line 518: [: : integer expression expected
  {1} fioa 3.3 0.1 0.3 98.5 1.4 0.4 22% 0
  {1} fioa 3.3 0.1 0.3 98.5 1.4 0.4 22% 0
  {1} fioa 2.9 0.3 1.4 85.4 2.8 1.0 29% 0
  {1} fioa 2.9 0.0 0.3 96.0 1.5 0.4 22% 0
  {1} fioa 3.3 0.1 0.3 94.1 1.3 0.4 22% 0
  {1} fioa 2.6 0.1 0.8 100.8 4.7 1.3 36% 0
  {1} fioa 3.6 0.1 0.2 40.9 0.7 0.6 11% 0
  {1} fioa 3.2 0.1 0.4 146.6 2.5 0.5 31% 0
  {1} fioa 2.8 0.2 0.9 85.7 8.2 2.7 30% 0
  {1} fioa 2.9 0.2 0.9 84.9 12.6 4.4 29% 0
  {1} fioa 2.8 0.2 1.0 94.6 3.2 0.9 33% 0
  {1} fioa 3.7 0.1 0.3 90.9 1.4 0.4 21% 0
  {1} fioa 2.8 0.3 1.8 95.2 8.2 2.6 30% 0
  {1} fioa 3.0 0.1 0.3 92.0 1.3 0.4 20% 0
  {1} fioa 2.9 0.2 1.3 91.1 3.8 1.2 30% 0
  {1} fioa 2.9 0.3 1.4 85.0 3.7 1.2 41% 0
  {1} fioa 2.1 0.8 5.8 68.4 15.1 6.5 62% 0

first two lines are kind of unexpected output
and there is also no header for statistics.