I searched for this problem and, from what I found, it seemed that those suffering had an older version of php running. That isn't my issue.
Drupal 4.6.0
php 4.3.9
When cron.php is run through crontab I get about 10 pages of the following error:
Compilation failed: characters with values > 255 are not yet supported
in classes at offset 143 in /home/[private]/public_html/modules/search.module on line 265.
The line in search.module alternates between 265 and 257 -- over and over and over and over.
What's worse, the site was not really being indexed when cron ran. Although it would tell me that 100% had been indexed, I could search for a term that I knew was there and it would say "no results." I went into the search.module administration area and changed the minimum size to be indexed (to force a complete reindex). Then I ran cron.php through the browser. This fixed the indexing problem as far as I can tell.
When I do push cron.php through the browser, however, I get the following error (just one time - not repeated like the crontab):
Cannot modify header information - headers already
sent by (output started at /home/[private]/public_html/cron.php:2) in
/home/[private]/public_html/includes/common.inc on line 99.
When the cron runs automatically, I've set it to deliver any results to my email. I get this same message in email after each run.