You need to use the method .LoadFile
if you want to load an assembly from a file path:
var assembly = Assembly.LoadFile(parameters.OutputAssembly);
^^^^
According to the documentation, the method .Load
:
Loads an assembly given the long form of its name.
It expects an assembly name, like SampleAssembly, Version=1.0.2004.0, Culture=neutral, PublicKeyToken=8744b20f8da049e3