Errors while running virtualmin-install.sh

[chris001]

./slib.sh: line 306: [: : integer expression expected
./slib.sh: line 306: [: : integer expression expected
./slib.sh: line 306: [: : integer expression expected
./slib.sh: line 29: which: command not found
error: process ID out of range

Usage:
 ps [options]

 Try 'ps --help <simple|list|output|threads|misc|all>'
  or 'ps --help <s|l|o|t|m|a>'
 for additional help text.

For more details see ps(1).

EDIT: Current version of virtualmin-install.sh from repo.