My ISP recently upgraded to PHP5.3. It gave me several problems because this PHP version is not yet supported by Drupal (will be in Drupal 7). However several work-arounds are available and well documented in this forum.
One issue however I did not find yet. On the page that displays the modules (site construction) some errors like below occur:
warning: syntax error, unexpected BOOL_TRUE in modules/<any module>/<any module>.info on line 3 in /.../includes/module.inc on line 195.
Probably it has something to do with the gtrans module I'm using, but I'm not sure. Anyway I found a working solution that I like to share with anyone having the same problem. I will answer my own question for this (split personality ;-) ).