While installing ubuntu, the installer crashed

[rahul mishra]

The installer crashed.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.12
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CasperVersion: 1.394
CurrentDesktop: ubuntu:GNOME
Date: Sat Mar 30 23:08:58 2019
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed cdrom-detect/try-usb=true noprompt floppy.allowed_drive_mask=0 ignore_uuid boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
ProcEnviron:
 LANGUAGE=en_IN
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Foundations Team Bug Bot (crichton)]

Exception during installation:
Mar 30 17:38:43 ubuntu /plugininstall.py: UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 70: invalid start byte
Mar 30 17:38:43 ubuntu /plugininstall.py:

[Brian Murray (brian-murray)]

Here's a more complete error message:

Mar 30 17:35:14 ubuntu ubiquity: Error in function update
Mar 30 17:35:14 ubuntu ubiquity: message repeated 2 times: [ Error in function update]
Mar 30 17:35:16 ubuntu systemd-resolved[1159]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
Mar 30 17:35:23 ubuntu ubiquity: E:
Mar 30 17:35:23 ubuntu ubiquity: The repository 'cdrom://Ubuntu 18.04.2 LTS _Bionic Beaver_ - Release amd64 (20190210) �/dists/bionic/main/binary-amd64/ Release' does not have a Release file.
Mar 30 17:35:23 ubuntu ubiquity: E: The repository 'cdrom://Ubuntu 18.04.2 LTS _Bionic Beaver_ - Release amd64 (20190210) �/dists/bionic/restricted/binary-amd64/ Release' does not have a Release file.
Mar 30 17:37:31 ubuntu /install.py: Terminated ubiquity update process.
Mar 30 17:37:31 ubuntu ubiquity: UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa0 in position 70: invalid start byte