128M need in PHP5.2.5 instead of 8M in PHP5.1.4!

Hello! My first message: I've just updated PHP from 5.1.4 to 5.2.5 (to solve an Apache problem when double-clicking on links). This was successful, as the problem is now solved, but I now, sometimes, get a message stating that the memory is exhausted. I modififed php.ini and set memory_limit to 16M (instead of 8M with PHP5.1.4), then 32M, then 64M, with the same message. With 128M, it works. Can this change in memory required be considered as normal? I don't think so... Is there any explanation? Details: - Platform: Windows. - I used Windows binaries (no C compiler available). The part causing the error uses jpgraph (for generating .png files) and the png files are used when generating a PDF file (by the tcpdf library) (the gd extension is used). A second issue with this release: When I made the tests decribed above, I used 'restart' to restart the Apache server, with no error message. When I tried to stop Apache and start it again, I got an error message stating that the zend_unmangle_property_name_ex entry cannot be found in php5ts.dll, and I now get this message each time I restart Apache (Apache2.2),. But it seems that Apache works normally nonetheless. I made sure that the php5ts.dll used is the right version for 5.2.5. Any idea? Thanks for any suggestion!