Poretools yield plot function not working

[NathanielLegall]

The yield_plot function gives me a plot where all the reads are produced at the same time. We produced the 1D data using MinKNOW 1.4.2 with a rapid kit.

poretools yield_plot --plot-type reads /home/nlegall/MinION_Lambda/data/downloads/pass

Poretools was built on an ubuntu server, not sure if that makes a difference but any suggestions on how to resolve this would be appreciated.