Undefined subroutine error (only now and then)

[Paulo Narciso Filho <na...@harbor.com.br>]

I'm using Apache and mod_perl to develop a dynamic web site. When I 
execute a specific script for the first time (after restarting 
Apache, for instance), it always works. If I reload the page, I
(sometimes) get the following message in my apache error log:

[error] Undefined subroutine &Apache::ROOTagv_2eembra
co::perl::agvs::agvs_2ecgi::GetUser called at (file_location) line 
19, <frame2> chunk 35.

The subroutine is there (it executes in the first time). If I keep 
trying to reload the page, sometimes it works, sometimes it doesn't.
The same error happens to other scripts, with different subroutines 
being called, but never happens if I run them from the command line
(with the scripts slightly modified).

some things from the server configuration:

PerlInitHandler Apache::StatINC

<Location stuff>
SetHandler perl-script
PerlHandler Apache::Registry
Options ExecCGI
allow from all
PerlSendHeader on


Can anyone help?
Thanx

Paulo