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Unfortunately PetalsBPM cannot always be used on IE.
The reason is : we use a library for graphic vectors using both SVG (Chrome, Firefox, Safari, IE 9-...) an VML (for old IE versions). And this library does not totally implement VML whereas it does for SVG.
In fact IE version 9+ supports SVG natively, so perhaps you cannot run PetalsBPM on IE because you have a too old version of IE.
Either way, I would recommand you use Firefox because we have detected some bugs with Chrome, and as you know PetalsBPM and IE are not best friends.