Invalid EUC_JP char seq bug?

I am using PHP with postgreSQL and I have been getting a few rare errors
while trying to do selects on a table containing EUC_JP text.

I thought it was a bug with PHP not recognizing a string as invalid
EUC_JP characters and wrote up a bug report but the PHP developers
assure me that the string that is generating the error is a valid EUC_JP
string (I don't know anything about character encodings so I am taking
them at their word and the fact that the string displays fine in my
browser as EUC_JP lends me to suspect they might be right).

The offending string is url encoded as such:

words=%8f%ac%90%ec%96%be%93%fa%8d%81

When I try and do a SELECT I get the following error:

select id from products where name like '??????'
Query failed: ERROR: Invalid EUC_JP character sequence found (0x8100)

(Where did the 0x00 come from??)

Can someone let me know if this truly is a bug in postgres?

Thanks,

Jean-Christian Imbeault

PS I have also had the error pop up with this string:

search_words=%B7%F6%BA%7E
select id from products where name like '??~'
Query failed: ERROR: Invalid EUC_JP character sequence found (0xba7e)