Guillermo,
Unfortunately, there is no direct path between 6.0(1) and 6.1(4). If your target is 6.1(4), you will need to upgrade first to v6.1(2), then you can upgrade to CUCM 6.1(4). But so you are aware, the 6.1(x) brach of code had an end of sale announcement in March of 2010. I would strongly recommend moving to the 7.1(5) release or even the 8.0(3) release to keep current with CUCM releases.
For the supported upgrade matrix and EOS announcement:
http://www.cisco.com/en/US/partner/docs/voice_ip_comm/cucm/compat/ccmcompmatr.html
http://www.cisco.com/en/US/partner/prod/voicesw/ps6788/vcallcon/ps556/end_of_life_notice_c51-589088.html
Thanks,
Dan Keller
Technical Marketing Engineer