[Typo3-windows] Online extension repository not working

[Jaco Oversluizen]

I tried several times to download online extensions via the ext. manager. At
all times I get this message:

 Fatal error: Call to undefined function: is_executable() in
E:\Download\Developing\website\typo3\testsite-3.5.0\typo3\mod\tools\em\index
.php on line 2647

It seems to me that all such kind of messages along this newsgroups are
categorically neglected. I asked myself why does that happen? Can anyone
help me with this problem, because by myself I have not any clue
how to solve this problem.
Lots of files, not a great knowledge of PHP :-)

 My installation is Windows xp with IIS 5.1 (of course), MySQL 3+ PHP 4.3.1
using the latest typo3. All suites have this problem. When asked I will give
you further details.
 -- 
 <>< A Dieu
 Jaco Oversluizen