This is less of a question and more a request that someone with the proper contacts can get a bug report in to the Access developer team.
There is an old bug in Access 2007 that still exists in fully updated versions of Office 2007. The problem is that when using the query designer to generate an append query against a table with spaces in field names brackets are improperly inserted into
the designer where they do not belong. The brackets around field names should only be in the SQL text, not in the designer. I've attached 2 pictures that depict the problem. The first is the automatically generated field names by the design; New Query -> Select
Table & Fields -> Append Query -> Select Table to Append To. If you select the field with brackets around it from the field name drop down the brackets are automatically removed and the append query is now functional. Additionally you can open the SQL view
of the query, insert a space at the end of the query (or any modification) and go back to design view and the brackets are gone and the append query will now work.
I realize that using spaces in table names and field names goes against best practices and I personally don't do it however Access does allow it and people who have no idea about the pitfalls indeed add spaces into their table and field names and then
wonder why their append queries under Access 2007 are broken. It would be superb if sometime in 2014 we could finally get a patch for this 7 year old software that corrects this long standing problem with very basic functionality in the query designer.
Wrong (generated by access):

Right:
