When I ran your code under Perl 5.10 with warnings enabled, I got:

C:\PerlProjects\Monks>perl regextest.pl
Start Basic Standard Services:
  Starting $name='ONC RPC PortMapper' $last='Config' ($name=~/$last/i)
+=0
  Starting $name='OP Time Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Log Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Configuration Server' $last='Config' ($name=~/$la
+st/i)=1
Start Remaining Standard Services:
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 27.
  Starting $name='OP Data Server' $last=undef ($name=~/$last/i)=1
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 28.
Start General Services:
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 38.
  Starting $name='OP Monitor' $last=undef ($name=~/$last/i)=1
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 39.
Installation completed

C:\PerlProjects\Monks>perl regextest.pl asdf asdf
Start Basic Standard Services:
  Starting $name='ONC RPC PortMapper' $last='Config' ($name=~/$last/i)
+=0
  Starting $name='OP Time Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Log Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Configuration Server' $last='Config' ($name=~/$la
+st/i)=1
Start Remaining Standard Services:
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 27.
  Starting $name='OP Data Server' $last=undef ($name=~/$last/i)=0
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 28.
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 27.
  Starting $name='OP Calculation Server' $last=undef ($name=~/$last/i)
+=0
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 28.
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 27.
  Starting $name='OP OPC Client' $last=undef ($name=~/$last/i)=0
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 28.
Start General Services:
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 38.
  Starting $name='OP Monitor' $last=undef ($name=~/$last/i)=0
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 39.
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 38.
  Starting $name='OP Mover' $last=undef ($name=~/$last/i)=0
Use of uninitialized value $last in regexp compilation at regextest.pl
+ line 39.
Installation completed
[download]

I added:

sub startStandardServices {
    my $last = shift;
    $last //='EVERYTHING'; #ADDED

sub startGeneralServices {
    my $last = shift;
    $last //='EVERYTHING';  #ADDED
[download]

And got the same results with or without command line args. I think the logic needs to be modified somewhat to get what you want. the main thing is get rid of this "undef in regex" warning.

C:\PerlProjects\Monks>perl regextest.pl
Start Basic Standard Services:
  Starting $name='ONC RPC PortMapper' $last='Config' ($name=~/$last/i)
+=0
  Starting $name='OP Time Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Log Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Configuration Server' $last='Config' ($name=~/$la
+st/i)=1
Start Remaining Standard Services:
  Starting $name='OP Data Server' $last='EVERYTHING' ($name=~/$last/i)
+=0
  Starting $name='OP Calculation Server' $last='EVERYTHING' ($name=~/$
+last/i)=0
  Starting $name='OP OPC Client' $last='EVERYTHING' ($name=~/$last/i)=
+0
Start General Services:
  Starting $name='OP Monitor' $last='EVERYTHING' ($name=~/$last/i)=0
  Starting $name='OP Mover' $last='EVERYTHING' ($name=~/$last/i)=0
Installation completed

<c>
C:\PerlProjects\Monks>perl regextest.pl asdf asdf
Start Basic Standard Services:
  Starting $name='ONC RPC PortMapper' $last='Config' ($name=~/$last/i)
+=0
  Starting $name='OP Time Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Log Server' $last='Config' ($name=~/$last/i)=0
  Starting $name='OP Configuration Server' $last='Config' ($name=~/$la
+st/i)=1
Start Remaining Standard Services:
  Starting $name='OP Data Server' $last='EVERYTHING' ($name=~/$last/i)
+=0
  Starting $name='OP Calculation Server' $last='EVERYTHING' ($name=~/$
+last/i)=0
  Starting $name='OP OPC Client' $last='EVERYTHING' ($name=~/$last/i)=
+0
Start General Services:
  Starting $name='OP Monitor' $last='EVERYTHING' ($name=~/$last/i)=0
  Starting $name='OP Mover' $last='EVERYTHING' ($name=~/$last/i)=0
Installation completed
[download]