Connecting to a 7.1 DB with 7.3 psql

I'm having trouble connecting to a 7.1 database with the 7.3.2 client.
It seems that my user privileges are severely restricted.
Check out this interaction:

----------------------------------
[demo@trout ~/database_dumps]# psql -Usts -h winnie sts
ERROR:  parser: parse error at or near "."
Welcome to psql 7.3.2, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
       \h for help with SQL commands
       \? for help on internal slash commands
       \g or terminate with semicolon to execute query
       \q to quit

sts=> select version();
                           version
--------------------------------------------------------------
 PostgreSQL 7.1.3 on i686-pc-cygwin, compiled by GCC 2.95.3-5
(1 row)

sts=> \l
ERROR:  parser: parse error at or near "("
sts=>
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The version of psql is obviously 7.3.2.  I compiled it myself from the SRPMs from postgresql.org on this RedHat 6.2
system(trout).  The server is obviously running on cygwin, and I don't suspect that's the problem.  What could be
happeninghere?  User sts owns the database named sts.  Connecting with a 7.1 client works fine. 

I'd appreciate any suggestions!

-Roland