Bicgstab Size of the matrix in Bicgstab


I would like to solve a linear system Ax = b. I am using Bicgstab to solve this system.
Here is the link to download.

I have a 512MB GPU NVIDIA getforce310M graphics card. My system is giving the solution to the system if the matrix dimension is less than 5000. Otherwise it is not giving the answer, It is saying inavlid index < 1. I don’t know how to solve this. Do you have any idea to overcome this difficulty?