harmless Apache redirection errors ?

Hi,

We are deploying several web applications on JBoss 3.0.7 (with Tomcat
4.1.24)
using Apache (2.0.48) as web server, redirecting requests via MOD_JK2
(2.0.43)
on Solaris 9.

It works fine on all our servers, however I have noticed tons of errors in
Apache error_log,
they all follow the following pattern:
[error] channelSocket.receive(): Error receiving message body -1 131

[error] workerEnv.processCallbacks() Error reading reply

[error] ajp13.service() ajpGetReply recoverable error 120000



Can you please tell if they are harmful, the cause and possible fix.

(They seem to be produced at every request).



Thank you in advance,

Oleg