Visual COBOL PE Installation

I've downloaded the following PE

Serial NumberProductVersionPlatform
600000522412 Visual COBOL for Eclipse Personal Edition 2.1.Update 1 x86-64 running Red Hat Enterprise Linux 5.5/5.8 32/64 Bit

When I run the installer it fails when checking for Disk Space as can be seen below:

Micro Focus Visual COBOL for Eclipse 2.1 - Update 1

Before installing and using this software product you must
agree to be bound by the terms and conditions of the end user
license agreement ("End User License Agreement") which
accompanies this product. Please take this time to read the
License Agreement. If you are not in agreement with the terms
and conditions of the License Agreement, please contact your
Account Representative.

If you require a copy of the License Agreement before installing the
product then answer no and run the installer with the command.

./setup_visualcobol_deveclipse_2.1_update1_redhat_x86_64 -EULA

Do you agree to the terms of the License Agreement? (y/n): y
./ line 307: [: 12%: integer expression expected
expr: non-numeric argument

Current disk space available - Mb
On disk product size - 434 Mb
Temporary disk space required - 1303 Mb - CheckDiskSpace - ERROR - Not enough disk space at /opt to install product.


Actually there is more than enough disk space as can be seen from df -k /opt

# df -k /opt
Filesystem 1K-blocks Used Available Use% Mounted on
47098232 5002120 39703640 12% /

How is the disk space being checked by the installer?

I'm currently trying to install on Oracle Linux 6 as opposed to Red Hat but that shouldn't be a problem.