Attachments !!! (I'm going crasy)

[Thomas GUTHMANN]

Hello,

I'm currently trying to install correctly IMP. It works great with basic
mail without attachment !!!

But, when i tried to attach a little file (such as a HTML file), it
still works great except the error message in the error_log (apache)
---Snip ----
<br>
<b>Warning</b>:  Mailbox is empty (errflg=1) in <b>Unknown</b> on line
<b>0</b><br>
<br>
<b>Warning</b>:  Mailbox is empty (errflg=1) in
<b>/var/lib/apache/htdocs/horde/imp/compose.php3</b> on line
<b>0</b><br>
---Snip ---

So, now a bit more difficult ! One file of 4,3Mo for example
When I click on the send button, I receive the message

"Document Contains no Data ...Contact Webadmin" (something like this)

And nothing happens, thenI click again on the send button and a window
appear fastly and close as fast as it appears
... and finally I receive the mail !

I watch my error log and I received this message
--Snip--
FATAL:  emalloc():  Unable to allocate 5827700 bytes
--Snip--

Any ideas ?

My config is
Php-4.0.2
horde 1.2.2
imp 2.2.2
mysql 3.22.32

P133 with 64Mo

In my php.ini
I modify (as said in the faq) :
--> upload_max_filesize = 20000000
-->memory_limit = 21000000
--> max_execution_time = 30

Hope you can help me ...

NB: excuse me for my bad english