Was thinking at first that perhaps you have hit upon an event limitation i.e. that it has to be the current event. However, I found that is not the case.
There is a table with file path; short text field, a form with a textbox to show the path and code that references the textbox. I found that it works either on current (as designed) and on button click.
The control is OLEbound as stated, with no Control Source or Source Item properties in design. I removed the initial Source Doc property and it still works. To test the button event, I simply move on to another record then click and it works. In spite of my implied notion that I wouldn't bother testing various types, I figured I may as well use the files that a different version came with since they're all in the same folder and dontcha know - it shows doc, pdf, xls and bmp. The pdf's load in a second, doc & xls take about 6.Code:' Specify source file. Me.OLEBound10.SourceDoc = CStr(Me.tbDocFile) ' Create link to. Me.OLEBound10.Action = acOLECreateLink