ubuntu installer could not partition my hard disk

[Soma Muthumanickam]

while using the ubuntu installer, I reached the section where I had to select how much hard disk space I wanted to allocate for ubuntu. when I selected a value and tried to proceed, I received and error and the installation stopper mid way

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: ubiquity 18.10.12
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CasperVersion: 1.399
Date: Sat Dec 8 17:45:03 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)