System.ArgumentNullException error with MonoDevelop compiling a c# code -

I have another simple question: I have a C # program which CC file has been written as MonoDevelop (Improved by Xamarin) managed to create this project. However, when I try to run it, I get an error:

  System.ArgumentNullException: the argument can not be zero. Parameter Name: On System.Double.Press (System.String S, Number Style Style, Imageform Provider Provider) [0x00012] In / Private / TMP / Monobild / Build / Build / Mono- 2.10.9 / MCS / Class / Coribib / System on /Double.csumer29 system.double.paras (system.restrictions) [0x00000] /private/tmp/monobuild/build/BUILD/mono-2.10.9/mcs/class/corlib/System/Double.cs: Sample Namespace at 200. Sample Class.mine () [0x00049] In / Inu / User / Ninaakulisova / Thoughtworks / Sales Inpu With Taxes Ts.cs: 42   
 which indicates the following line of code:   value [item number, 2] = double. Purse (quantity);   
 I find mysterious that there is no private / TMP / mobile / build / bootel / MO-2/10/9 / MCS / class / correlate / system / folder on my Mac And when I compiled this code on the online compiler, all went well. Do you know what can be wrong?  
 Thanks a lot!   
 
 
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 This folder is probably present on a machine compiling mono.  
 
 Check to see if  quant  is zero.