In your first "foreach" loop (just after the two while loops reading the two input files), you are not changing the value of $recnum1, which means that on every iteration of this for loop, you're using the last value that was assigned to that variable, which is the last record actually read plus one (i.e. a non-existent record in your %acs hash).

Apart from that, it looks like you're expecting your two input files to have the same number of lines, and that there's some trustworthy relationship between the corresponding lines of the two files (file1 line1 goes with file2 line1, and so on, to the end of each file). If that's what you're assuming, are you sure it's really true for those two input files?

Also, are you sure that your "csv" files do not contain commas embedded in field values? ("Proper" csv format would put quotes around fields that contain one or more commas as part of the data, and you'd want to use Text::CSV when you have csv files like this.)