"...messages like...." doesn't really cut it. Here are the messages which result from adding strict and warnings to your script and running...

perl -c 1045909.pl
Scalar found where operator expected at 1045909.pl line 16, near "$rea
+dingbooks$_"
    (Missing operator before $_?) # ie, Ln beginning '$rdbooks = $read
+ingbooks$_;'
Scalar found where operator expected at 1045909.pl line 17, near "$rea
+dingdate$_"
    (Missing operator before $_?)
Scalar found where operator expected at 1045909.pl line 21, near "$cat
+books$_"
    (Missing operator before $_?)
Scalar found where operator expected at 1045909.pl line 22, near "$cat
+date$_"
     (Missing operator before $_?)
Global symbol "$readingbooks" requires explicit package name at 104590
+9.pl line 16.
syntax error at 1045909.pl line 16, near "$readingbooks$_"
Global symbol "$readingdate" requires explicit package name at 1045909
+.pl line 17.
syntax error at 1045909.pl line 17, near "$readingdate$_"
Global symbol "$catbooks" requires explicit package name at D:\_Perl_\
+PMonks\1045909.pl line 21.
syntax error at 1045909.pl line 21, near "$catbooks$_"
Global symbol "$catdate" requires explicit package name at D:\_Perl_\P
+Monks\1045909.pl line 22.
syntax error at 1045909.pl line 22, near "$catdate$_"
1045909.pl had compilation errors.
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And... ohmigosh -- strict and warnings + actually reading the messages -- comes to the rescue again.