Dissapearing formulas

In one worksheet of my app I put some simple formula and as soon as I click the return button, the value turns to 0 and examination reveals that the formula has gone. This however is not consistent. Sometimes the formula is accepted for one instance and then goes and on one occasion it survived till I saved the whole app prior to closing it.
I have checked that calculation is automatic. What can be going on?
I have attached a copy of the sheet with the formulas but they are all working normally. The formulas are marked in yellow
John

TMS thank you for your interest. Those formulae with a long file path arose because I copied an earlier version sheet by sheet to this version as the earlier version had become corrupted somehow.
I have corrected them and still have my disappearing formulae. The problem is not that the formulae give an answer of 0, it is that the formulae are no longer there
Rorya thanks for you as well. Yes I have several controls using controlsource. Can this be a cause?
John

Rorya I didn't know that. So I must enter values in code ?
Userform1.textbox1.ControlSorce =.Range("a1").Value or
Userform1.TextBox1.Value = .Range("A1").Value
John

Still haven't managed to clear all controlsources.
I have tried the following to populate the listbox

Please Login or Register  to view this content.

I get the message "Could not set the value property. Type mismatch"
The range "Year" is a list of years in the control source.
I have tried changing the code to

Please Login or Register  to view this content.

I then get message "Type Mismatch" even less helpful

Try:

Please Login or Register  to view this content.

Thanks for that ByteMarks I tried it and got another strange Error message "Permission denied" I took this a bit further and this gave me a list of possible causes most of which related to file forming.
This one seemed most relevant,
You tried to write to a file that another process locked. Wait to open the file until the other process releases it.

I am running the code under the Change process is this right
John

We are getting away from my problem which is to populate a ControlSource with a named range without using the controlsource property by using vba. I don't think I have any interest in RowSource. If I can do that I am hoping that my other problems will go away, as it has been stated that lots of problems are caused by ControlSources
JHohn

You are dead right I was in a right muddle. Thanks for clearing it up.
Is it safe to enter the range using the rowsource property or best to use code?
John