[Typo3] extension install weirdness

[David Cake]

	OK, I found a work around for my problem with installations installing.
	The work around is that extensions do not install if I use 
the extension manager (it returns no error, but simply does not list 
the extension as installed no matter what I do), but if I attempt to 
install the extension via the extension manager, and then use the 
install tool to add the name of the extension to the list of 
installed extension, they then work.
	Any suggestions as to what is causing this behaviour?
	(as mentioned before, Debian stable, typo3 3.8 upgraded from 3.6
	Regards
		David Cake