File handle FH opened only for output at submit.plx line 53

Hello scripters,

I made a script (submit.plx), which records the visitor's details into a
text file and then another script (table.plx) that puts them into a table.
But I receive the error: File handle FH opened only for output at submit.plx
line 53. Here's my code:

open TXT, ">>contacts.txt" or die $!;
print <TXT>, @details;
close (TXT) or die $!;

It's exactly like on the manual. Any suggestions?