Windows XP SP2 and IE Version Question

Archived from groups: microsoft.public.windowsxp.security_admin (More info?)

What is the difference between a version of:

6.0.2900.2180.xpsp_sp2.rtm.040803-2158

and:

6.0.2900.2180.xpsp_sp2.rtm.040803-2158c

Does anyone know what the 'c' at the end of the version stands for? We have
a situation where 5 workstations all have windows xp with sp2 installed and
the same version of IE except that one workstation has the 'c' at the end of
the version. This is the same workstation that has a problem with accessing
a web site that requires a login and stores a cookie on the machine. After
each successful login, if the user on that work station wants to access that
same site again, he/she must delete all cookies or else it will not work.
Any ideas?

TIA.