Apache asking for password multiple times

When I use Front Page Extensions (FPE) to create a protected folder I am
often prompted for the password many times before access is granted.
My hosting service has the following installed:
Linix:RedHat 7.3
Apache: 1.3.27
Front Page Extensions: 5
mod-dav (Allows read/write access to files)
(All security handled by Apache, not mod_dav)

I have uploded an Excel spreadsheet (.xls) file to a folder in my web site.
The .xls file is not password protected by Excel. Using FPE, I set the
folder to:
Use unique permissions
Only registered users can browse
One username/password (just called "pw" below) with browse only
Another pw with browse & author permissions.

When I use Excel to open the file (File/Open http://MyDomain/path/jnk.xls)
I am prompted for the pw. If I enter the pw with author permission, the
spreadsheet immediately opens with read/write access as it should.
However, if I enter the browse only pw I am asked tor the pw many times,
and then finally read-only access is granted as it should be.

The question is why I am prompted for the pw so many times and what can I
do so I am only prompted once?

I have tried all sorts of changes to .htaccess in the folder where the .xls
file is. Some changes caused it not to work at all, but all the working
ones I tried failed in the same way.

In case they are helpful, here are 5 different scenarios which may help to
understand just what is happening:

Scenario 1 - Enter pw at every prompt:
1.pw request for Resource http://MyDomain/t/jnk.xls, I enter correct pw
(do above a total of three times. Note: the AuthName in the folder's
..htaccess is simply "t")

2."File transferring" message briefly displayed

3. pw request for Resource http://MyDomain/t/jnk.xls, I enter correct pw
(do above a total of three times)

4. Read only copy of spread sheet opens & is ready to use.

Scenario 2 - Enter pw at 1st promot only:
1. pw request for Resource http://MyDomain/t/jnk.xls, I enter correct pw
(One time only)

2. pw request for Resource http://MyDomain/t/jnk.xls, I click on "Cancel)
(One time only)

3. "File transferring" message briefly displayed

4. pw request for Resource http://MyDomain/t/jnk.xls, I click on "Cancel)
(One time only)

5. Read only copy of spread sheet opens & is ready to use.
(Note I was only challenged for the pw 3 times instead of 6 as in scenario
1)

Why all the additional prompts when it didn't "care" if I gave it or not?

Scenario 3 - Enter P/W on last prompt only:
1. pw request for Resource http://MyDomain/t/jnk.xls, I click on "Cancel"
(One time only)

2. "File transferring" message briefly displayed — Strange?!!?

3. pw request for Resource http://MyDomain/t/jnk.xls, I click on "Cancel"

4. pw request for Resource t, I enter correct pw
(t is the AuthName in .htaccess)

5. Read only copy of spread sheet opens & is ready to use.
(Note I was only challenged for the pw 3 times instead of 6 as in scenario
1)

Scenario 4 - Never enter pw:
1-3. Same as scenario 3

4. pw request for Resource t, I click on "Cancel"
(t is the AuthName in .htaccess)

5. Message box: "Microsoft Excel cannot access the file ..."