Problems with web installer

Hello to all, since yesterday I very often get an "install failed", when I try to install packages via web installer. On my own domain (shared hosting PHP 4.4.1), where all worked fine before, some packages throw this error and won't install. I had this "channel-update" warning last week, but nevertheless the packages could be installed. On a second shared-hosting-server with PHP 4.3.11 I yesterday installed pear for the first time with go-pear 1.7.8. There have beeen the channel-update-warnings, too, but no other error messages. But the web installer lists no installed packages and there every trial to install ends with an "install failed". Just one time I got "Cannot install, php_dir for channel "pear.php.net" is not writeable by the current user". I tried go-pear 1.7.6, too, but it quits with a fatal error "no class pear defined in line 668?" (around that). Has anybody an idea? Are there problems on my servers or is it a momentarily problem with the pear-server? And what can I do alternatively? The installation on the second server is a bit urgent. Thanks on advance Sabine