failed requests when benchmarking with ab command

[flumpydog]

I am attempting to troubleshoot some problems on one of our servers.

When I run Apache Benchmark on a file that contains an include to another file that does not contain an include itself to other files, all appears ok.

If the file being called via an include, also contains include statements to other filesl, then I get a large number of failed requests.

This page contains php includes to other files that again have their own php includes:
ab -n 200 -c 20 http://www.domain.com:80/test.php
Concurrency Level: 1
Time taken for tests: 1.130198 seconds
Complete requests: 200
Failed requests: 91
(Connect: 0, Length: 91, Exceptions: 0)
Write errors: 0

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This page only contains primary php includes, none of the files called have php includes to other files in them
ab -n 200 -c 20 http://www.domain.com:80/test2.php
Concurrency Level: 1
Time taken for tests: 0.862251 seconds
Complete requests: 200
Failed requests: 0
Write errors: 0

I am running Apache 2.0.40 with PHP 4.2.2

Any help will be greatly appreciated!

Thanks,
Charlie