Little problem with RF module

[Mathy]

Hello,

I use the RF component on a 18F26k22 family.
The RF component is on the first SPI hardware peripheral and one SDCARD and one accelerometer and the second.

I use the polling method to check the buffer and then read the FIFO.
The fist problem I have is when I set a to large timeout value ( 20 ) when checking the buffer, I don't know why but the stored data are corrupted. I receive 0x02 instead of 0x01.
This is appening only if I do some calculation with the accelerometer and the SDCARD. If I don't use them, no problem.

If I set a small timeout value like 2, no problem even if I use accelerometer and sdcard. Do you know why ?

Thank you for your help.