Issue when inserting Slovak characters in database via PHP code

Hi,

Sorry to cross post this mail but i'm not able to know from where comes my
issue.
I have a postgreSQL database in UNICODE (UTF-8 in v8.1.4 and UNICODE in
v8.0.1).

Via my web application i type a sentence in Slovak language and it is stored
into DB without any slovak characters. Instead of that, all particular
characters are replace with \303\251 or \303\206 or \304\314 and so on...

I was thinking that issue was coming from DB encryption but on 2 different
versions of DB (see above) i get the same result.
after, i was thinking that it was coming from my web browser, but even if i
setup character mode in central europe and Slovak language as default
coding...nothing change...i tried on IE and Firefox.

Last step, i tried to type directly from my PhpPgAdmin (direct typing
sentence there to DB), and i realize that when i click on save...the changes
appear in DB aswritten above (e.g. : \303\251,...)

My latest test was to write via PhpPgAdmin (directly to DB) the UNICODE of
slovak character contained within my sentence...so i used &#253, &#237 and
so on...
if i do that, those code are correctly saved into DB and when my PHP code
show web pages, all sentences are correct.

I can not imagine to write a special interface to convert slovak characters
to unicode everytime that user would like to type something new.
Something else must be badly setup...

Please, could you tell me where to search because i'm confused now...

thx.

Alain