How do you use gsub to remove ¬ character on iOS?

I’ve tried using gsub to remove a ¬ character from a url, as it shouldn’t be there but has been added by a client’s server.

Is there a way to remove it? I tried this:

url = string.gsub(url, "¬", "")

print(url) system.openURL(url)  

The print statement prints the url correctly:

http://www.pharmatimes.com/Article/13-09-12/Oxford\_BioMedica\_bags\_£7\_1m\_UK\_govt\_grant.aspx

however the system.openURL call returns an error saying:

WARNING: url( http://www.pharmatimes.com/Article/13-09-12/Oxford\_BioMedica\_bags\_£7\_1m\_UK\_govt\_grant.aspx ) is not supported by the simulator

For this url, the call doesn’t work on iOS or the simulator, but does work on Android (even without using gsub).

Why would it use the same string in 2 different ways?