<somewhere in machine>\epiktimer-0.2\epiktimer.pas(320,3) Fatal: Selected assembler reader not supported
any idea ? 
fpc : 2.5.1
os : xp
Well, first always post what is on that problem line with a bit of context.
But my guess is that it is {$asmmode direct} as used in very old FPCs. Probably the piece of code is 10 years old or older.
It probably has to be updated, but it will probably need more modifications (for e.g. general 1.0.x-2.0.x changes).
($asmmode direct simply copied the asm block to the backend assembler without modification. One couldn't use e.g. paramnames in that mode. It was later replaced by asmmode ATT, and even later also asmmode intel appeared)