../../SharedFiles/spiInterface.c:838: error: static declaration of '__vector_5' follows non-static d

Hello to those who know better,

by compiling a .c File i get the message
../../SharedFiles/spiInterface.c: In function '__vector_17':
../../SharedFiles/spiInterface.c:838: error: static declaration of 
'__vector_5' follows non-static declaration


Of course i tried to Google it, but the hits i get aren´t helping me.
The joke is, the message is coming from a file which is shared by two 
Projects. One Project is compilable, the other isn´t. Both are compiled 
with the same comiler.

It´s Code for a Mega32A. What i don´t understand are the vector numbers. 
__vector17 is ADC conversion done INT, and __vector5 is TIMER2_COMP INT, 
but by clicking the message i´m forwarded to the SPI Complete INT.

can anyone solve this puzzle?

PS.: sorry i don´t post code, since it´s a Company Thing...