Unable to register APToolkit After installation

I am Getting (-998) error.
When I m creating Pdf file.using APtoolkit objecl


my code is


Toolkit objTk = new Toolkit();
Int32 i= objTk.OpenOutputFile(@"D:\ActivePDF\Sample1.pdf");
Int32 j= objTk.OpenInputFile(@"D:\ActivePDF\Sample.pdf");
objTk.SetFont("Arial", 20);
objTk.PrintText(200, 700, "Title");

objTk.CloseOutputFile();
objTk = null;
if(i==0)
{
Response.Write("Success");
}
if(i==-1)
{
Response.Write("Unable to open FIle");
}
if(i==-998)
{
Response.Write("Less Permission or not register");
}