zbar in c# by using libzbar.dll or libzbar.a

Hi ,
I want to use the zbar for barcode reading in IOS primarily. This may be cross platformed to windows too. I downloaded the libzbar.dll and tried to Pinvoke the methods which I listed via dumpbin /export.
 
I am getting a Pinvoke stack imbalance exception (?).
The questions are
 
1) How to avoid the stack imbalance? ie how to find the parameters for methods in the dll?
 
2) Is it ok to use *.dll file when I build for IOS or Can I do that at all?
 
Other than that any info on using a libzbar.a for cross platform development is appreciated.
 
Thanks