Regrettably, many marriages having difficulty are dissolved in civil tribunals. Civil divorce in and of itself does not automatically bar Catholics from receiving the sacraments. But because the Church holds the bond of marriage as an indissoluble bond, sacramentally witnessing to the undissoluable covenant of fidelity between God and His Church, remarriage is not possible within the Church unless it can be proven that some fundamental element of marriage was lacking on part an earlier attempt at marriage.

The process of determining if a marriage lacked one or more of the substantive elements of the sacrament is known as the ‘annulment process’. This link to the diocesan website can tell you more about the process.  Interested persons may contact the Diocesan Tribunal at the Catholic Pastoral Center: (217) 698-8500.

Additional information about resources available in the diocese for divorced persons can be found here.

-- Diocesan Links --
FAQ on Marriage Processes: Dissolution and Nullity (via the Diocesan Tribunal) Catholic Times Article on Marriage Annulments
FAQ About Tribunal Processes (via the Diocesan Tribunal)

-- External links --
Answering Common Questions about AnnulmentsEdward Peters via Catholic Answers