[imp] Problem Sub-option "Mail"

[Josiane]

Hi, There!
	I need some help with a problem that I can't figure out. I'm running IMP version 4.0 Horde 2.24, Apache 2.047 and PHP 4.33 under a Linux Slackware x.x.
	After a successful login, sometimes I get a initial screen with pure javascript code. Otherwise, the same screen appears when I select the sub-option "Mail", under main option "Mail & News".
	It seems that browser can't understand the code. I made some changes on source code but nothing happened.
	
	Can someone point me a direction? 
	A screenshot can be found at http://php.bortoli.com.br/Horde.png

Thanks,
	Josiane