Use DOS to combine text files

This is a two part question.  I am performing some data mining
routines for a client who has provided the following system
configuration:

Windows 7-64Bit
8Gig of Ram
Monarch v 10.5
Office 2007

Part 1:
I have several text files that I am combining with the following
name structure:
"xxxx xx xxxxxx.txt"

Within a batch file I issued the following command line:
COPY *.Txt "H13P46 LDistrb YTD.Txt"
This command works fine but select files within the combined file
are rejected by Monarch as exceeding "4000 character line"
None of the lines are greater than 256 characters - not sure what is causing
the error.  Combine works fine except Monarch cannot read it.

However, Monarch can read each individual file without any problems.

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Part II:
To alleviate the problem above I tried combining the text files as follows:
For %%F in (*.txt) do type %%F >> Output.txt

If I copy the command from within DOS it works fine; AND Monarch has no
problem reading the resultant combined file.
If I try running it from within the batch file it fails to combine the files
because it does not recognize the file name: xxxx xx xxxxxx.txt;
the DOS error states it is looking for only the xxxxxx.txt portion of the name.
I have tried various items such as double/single quotation marks and still no
result.

My goal is to combine multiple text files into one text file and then proceed to
run multiple Monarch routines from within the Monarch Scripting.