We can't solve this.
Particularly for that complete absence of information.
But you can...
What it is saying is that somewhere in your code (and the error message will specify exactly where) you have done the equivalent of this:
SomeClass variable = null;
variable.Property = value;
Or
SomeClass variable = null;
variable.Method();
And because the variable contains no object instance you can't access it's properties or methods.
It a bit like a car: if you don't specify which car ("This car", "That car", "My car", or "Your car") you can't access it's glove box (property) or drive it (method).
When you know which variable is null - and this may mean using the debugger if it isn't a simple line of code - then you can use the debugger to find out exactly
why it's null.
But we can't - remember that we can't see your screen, access your HDD, or read your mind!
[edit]Typos - OriginalGriff[/edit]