The build fails for older perls, probably because the s///r syntax is used:
Output from '/opt/perl-5.12.3/bin/perl Build.PL':
Bareword found where operator expected at Build.PL line 343, near "s{/lib}{/bin}r"
syntax error at Build.PL line 343, near "s{/lib}{/bin}r"
Execution of Build.PL aborted due to compilation errors.
The build fails for older perls, probably because the s///r syntax is used: