Debugging errors of SAGA interpolation algorithms in QGIS Processing?

I encounter recurrent problems with the geoalgorithms that perform interpolations. No matter what technique I use I end with the following errors. As stated in the OGR tab QGIS 2.0 is unable to open a file in C drive. I have very little IT background so the message error is meaningless.

Is there anybody able to decrypt the message and solve the problem?

here this is the algorithm i used