SQL parse error

   Hello all,
  My following problem is:

swports=# select substring(cp from 1 for 4)::int4 from out2cp;
ERROR:  pg_atoi: error in "6.1,": can't parse ".1,"
  SQL syntax is apparently OK. When I omit the typecast, the query
works:

swports=# select substring(cp from 1 for 4) from out2cp;substr 
--------318231823182
-8<- text deleted ---
  The cp entries are varchars in form NNNN.N, where N is numeral.  So can someone explain why the parse error?
  Bye Borek

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BOREK LUPOMESKY                Usti nad Labem, Czech Republic, Europe
WWW: http://www.volny.cz/borekl/                  PGP keyid: B6A06AEB
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