Error: package or namespace load failed for 'ChIPseeker'
Simple, use the latest version of R and Bioconductor, now on version 3.6.1 and Bioconductor 3.9. Those are the versions that are supported. If you can't upgrade R, check that BiocManager::valid() is true, you might have ended in some inconsistency between Bioconductor versions. 

Looking at your sessionInfo, you seem to have some problems with the installed libraries, check and correct those too if possible