push @colvalues1, $allcols[0],':',$allcols[1],"\n";

This pushes 4 separate values onto the array. If @colvalues1 was empty before the operation, the push populates it like this:

17:27 >perl -MData::Dump -wE "my @allcols = ('abc', 'def'); my @colval
+ues1; push @colvalues1, $allcols[0],':',$allcols[1],qq[\n]; dd \@colv
+alues1;"
["abc", ":", "def", "\n"]

17:27 >
[download]

Perhaps you intended to concatenate these 4 fields into a single string?

17:28 >perl -MData::Dump -wE "my @allcols = ('abc', 'def'); my @colval
+ues1; push @colvalues1, $allcols[0].':'.$allcols[1].qq[\n]; dd \@colv
+alues1;"
["abc:def\n"]

17:29 >
[download]

That is, replace the commas (which produce a list) with dots (which concatenate).

Hope that helps,