ODBC error "The buffer was too small for the InfoValue."

I'm configuring a SQL Server 2K to replicate to PostgreSQL 9.2.4.

- SQL Server 2K (sp4) 32bit is running Win 2K (sp4) 32bit on a
VirtualBOX. ODBC PostgreSQL driver installed is latest compatible with
Win2K (9.01.02.00 ANSI). ODBC version is 3.525.1117.0;
- PostgreSQL 9.2.4 is running Win7 64bit on native;

PostgreSQL 9.2.4 is configured as Linked Server in Sql2K. There is no
firewall active in either servers. Both servers are connected in same
subnet (192.168.25.x).
Connections from Sql2K to PostgreSQL 9.2.4 are really slow - I don't
know why.
I've enabled logging so I can look into details and try to discover the
slowdown reason, and found that every connection throws the following error:

[524.782]CONN ERROR: func=PGAPI_GetInfo, desc='', errnum=-2, errmsg='The
buffer was too small for the InfoValue.'
[524.828] ------------------------------------------------------------
[524.844]            henv=01653B80, conn=01653BB0, status=1, num_stmts=16
[524.860]            sock=01656718, stmts=016587F8, lobj_type=-999
[524.860]            ---------------- Socket Info
-------------------------------
[524.907]            socket=660, reverse=0, errornumber=0, errormsg='(NULL)'
[524.922]            buffer_in=23422952, buffer_out=23427056
[524.938]            buffer_filled_in=2126, buffer_filled_out=0,
buffer_read_in=2126


Why is this happening?

Thanks,

Edson Richter