although i have run sequence jobs in Gaussian but i did not experience running sequence jobs after IRC calculation.

Anyways, looking at the input suggest that the main source of error may be lack of specifying checkpoint file name in the second job.

you are trying to read the geometry from Chk file but the software does not know the name of .chk file because you did not specify it. 

add

%chk=hexane2

as is the checkpoint file name in your first IRC calculation

thanks

Thank you! Normal termination managed to be reached.

Mr. Tobias,

Generally in your file there is not shown the molecule specifications. Is this test file?