Hi, welcome here
Reconfigure option "simply" re-generate configuration files and it's totally harmless.
It must be done everytime you update your server AND install any "smeserver-*" or "e-smith-*" package.
Since you are new to SME, I suggest you to read carefully (and at least twice) the documentation.
If you want to know How SME works, you should read the dev's manual too (at least Section 1 and section 2)
HTH
p.s. please define "this server is quite unstable and weekly requires a Restart to become operable" as it's very strange.. anyway, if you find something that should not simply works as expected, please open a bug in bugzilla, thank you
p.s.2 if you wish to know what is installed on your server and any customization, you can take a look at
/sbin/e-smith/autdittools/newrpms
and
/sbin/e-smith/audittools/templates
output
HTH