I couldn't find a proper solution as I was expecting to find. But to avoid the program get crash, I put a check before loading the pdf.
bool PDFAvailable = axAcroPDF1.LoadFile(PDFPath.ToString());
If the Boolean variable 'PDFAvailable' return true I'll load the PDF like below. Else a proper message is thrown.
bool PDFAvailable = axAcroPDF1.LoadFile(PDFPath.ToString());
if (PDFAvailable == true)
{
axAcroPDF1.LoadFile(PDFPath.ToString());
axAcroPDF1.setShowToolbar(false);
axAcroPDF1.Enabled = true;
}
else
{
MessageBox.Show("Selected PDF Template Is Locked By Another Application.", ""Test Application"", MessageBoxButtons.OK, MessageBoxIcon.Information);
}