Hello Birgit,

Your archive included several "._" scripts for some reason.  None of these were valid xml files, but since they have a .xml extension, the tool shed attempts to parse them which results in the error message you got:

not well-formed (invalid token): line 1, column 0

Here is the contents of your achive:

-rw-r--r--   1 gvk  wheel   6148 Jun  6 16:09 .DS_Store
-rw-r--r--   1 gvk  wheel    171 May 25 13:44 ._Calculate_TestVariants_Variant_Frequencies.xml
-rwxr-xr-x   1 gvk  wheel    171 May  3 19:19 ._Calculate_TestVariants_Variant_Frequencies_0_1_0.pl
-rw-r--r--   1 gvk  wheel    171 May 31 13:39 ._List_Unique_Variants.xml
-rwxr-xr-x   1 gvk  wheel    171 May  3 12:50 ._List_Unique_Variants_2_1_0.pl
-rw-r--r--   1 gvk  wheel   1950 May 25 13:44 Calculate_TestVariants_Variant_Frequencies.xml
-rwxr-xr-x   1 gvk  wheel   9242 May  3 19:19 Calculate_TestVariants_Variant_Frequencies_0_1_0.pl
-rw-r--r--   1 gvk  wheel  13625 May 31 13:39 List_Unique_Variants.xml
-rwxr-xr-x   1 gvk  wheel  22321 May  3 12:50 List_Unique_Variants_2_1_0.pl

I eliminated all of the "._" files and created a new archive which uploaded successfully.  I've attached the archive.