[php-maint] Bug#398987: Impossible to install php5-imap

[impossible to install php5-imap, complains about phpapi-20051025]

Package: php5-imap
Version: 5.1.2-1
Severity: grave
Justification: renders package unusable

at install time, I have the following message :

colibri:~# apt-get install php5-imap
Reading package lists... Done
Building dependency tree... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
php5-imap: Depends: phpapi-20051025 but it is not installable
E: Broken packages
colibri:~# 


-- System Information:
Debian Release: 4.0
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.17-2-k7
Locale: LANG=fr_FR at euro, LC_CTYPE=fr_FR at euro (charmap=ANSI_X3.4-1968) (ignored: LC_ALL set to C)