Migrating between versions. Problem with regexp

Dear friends,

I have the following problem.

libvar=# select version();
version
----------------------------------------------------------------
PostgreSQL 7.2.3 on i386-pc-bsdi4.0.1, compiled by GCC 2.7.2.1
(1 row)

libvar=# select '\\a\\à\\à\\.' ~ '\\a\\à\\à\\.';
?column?
----------
f
(1 row)

=======================================

libvar=# select version();

version
--------------------------------------------------------------------------------------------------------------
PostgreSQL 8.0.0beta1 on i686-pc-linux-gnu, compiled by GCC gcc (GCC)
3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk)
(1 row)

libvar=# select '\\a\\à\\à\\.' ~ '\\a\\à\\à\\.';
ERROR: invalid regular expression: invalid escape \ sequence

I am using:
This is perl, v5.6.0 built for i386-bsdos
When I receive a text from CGI I made quotemeta over it to avoid symbols
that may be met in regular expressions.
Then I made DBI->quote over the same string to avoid any sql injection;
The problem is that I use cyrillic and quotemeta put before every
cyrillic character a \.
Then DBI->quote make \ to \\.
And then when I use this string in regular expression in Postgres I
recevie an error in the new version of postgres.
Could anyone sugest solution to my problem.
10x in advance.
Kaloyan