einfach nochmal das Datenblatt zum Thema ISP lesen
Seite 304.

Even though the SPI Programming interface re-uses the SPI I/O module, there is one
important difference: The MOSI/MISO pins that are mapped to PB2 and PB3 in the SPI
I/O module are not used in the Programming interface. Instead, PE0 and PE1 are used
for data in SPI Programming mode as shown in Table 127.

Code:
Symbol      Pins  I/O  Description
MOSI (PDI)  PE0   I    Serial data in
MISO (PDO)  PE1   O    Serial data out
SCK         PB1   I    Serial clock
HTH