Pl download the attached rar folder, extract it and rename it as Pointofsale.exe. 
Please copy this new Pointofsale.exe to the Point of sale client folder by renaming the existing Pointofsale.exe as Pointofsale_exe.
Please run the newly copied Pointofsale.exe for one time and then replace it with the existing Pointofsale.exe(Pointofsale_exe should renamed as Pointofsale.exe) and then check for the ITPS booking issue.
Thanks & Regards
P.Silambarasan DSM ,O/o Postmaster General,  
Southern Region,Madurai, Tamilnadu Circle
Mobile :+91 98420 31341