Amiga Forever 2010 Amiga software install prob

[Thomas]

The drive itself has 26GB free.

Fill it up until it has only 25.9 GB free. In general, divide the free space by 4GB and if the remainder is less than 2GB, it's ok. Numbers bigger than 2GB are treated as negative and thus smaller than even the smallest amount of needed space.

The same happens when the remainder reaches 0, i.e. if the drive has exactly 24 GB free for example.

[Thomas]

Why do you call it strange? Calculate the free space in bytes and try to store it in a signed 32-bit integer. It does not fit. The highest number which fits in 31 bits (the 32nd bit is used for sign) is 2G. Everything between 2G and 4G is treated negative (because the 32nd bit is set) and 4G is treated as 0.
Imagine a calculator with 8 digits. What does it do when you try to calculate with billions?
Or the miles counter in your car. What does it display when you drive more then 999,999 miles?

Creating a dedicated partition for Amiga-only files (i.e. installed programs) is nonsense. WinUAE can use VHD files which take only as much space as is used by files in it. For data sharing between Windows and AmigaOS you can still use your 26GB partition. Just use a copy program which can deal with large sizes.