It would make more sense if you actually showed your attempt to install mod_perl, since that's what you're having problems with. Also, formatting your posts properly makes it easier for people to help you. Please read and understand How do I post a question effectively? and PerlMonks for the Absolute Beginner. See also README.solaris and the mod_perl docs for 64bit compilation of Perl. IIRC you'll need to specifiy the CFLAG -m64.

I apologize for not following netiquette
I am essentially doing this:
perl Makefile.PL MP_APXS=/apps/apache/prefork/bin/apxs
make -j 128
that's when I encounter the error
make: *** modperl_lib Error 2
I am not a perl programmer, I am a systems admin tasked to do this.
anyway, scrolling upwards in my putty session, I see this message:
Manifying ../blib/man3/Apache2::Reload.3
"modperl_perl.c", line 272: undefined symbol:
PL_rehash_seed
"modperl_perl.c", line 273: undefined symbol:
PL_rehash_seed_set
cc: acomp failed for modperl_perl.c?
make1: *** modperl_perl.lo Error 2
make1: *** Waiting for unfinished jobs....
Manifying ../blib/man3/Apache::Reload.3
I do not need the -m64 flag, it is for gcc, I am, as mentioned before using Sun's solarisstudio compiler and I read the docs, they recommend using the same compiler.
I have in OP given the flags used to successfully build perl 64 bit

"I apologize for not following netiquette"

And still you ignore the post formatting advie which is clearly shown each time you do so.

" I am a systems admin tasked to do this. anyway, scrolling upwards in my putty session, I see this message:"

Consider employing one of the many techniques for storing what's happening. This is fairly basic sysadmin behaviour.

perl Makefile.PL MP_APXS=/apps/apache/prefork/bin/apxs
[download]

Unless you've done something you're not telling us, this will call your system perl, not the perl you just built into /usr/perl5/5.18.0. If this is not the case you're wasting our time and yours by not providing sufficient detail help resolve your issue.

"they recommend using the same compiler."

True, you should use the same compiler for both.

"I do not need the -m64 flag, it is for gcc, I am, as mentioned before using Sun's solarisstudio compiler"

You mentioned you had tried and failed with both gcc and sun compilers. I linked to documentation which still may be pertinent as it covers Sun studio on UltraSparc. Since you don't tell us which architecture you're on we can only point out potential issues.