Problems netwoking ms office apps on mixed PC/Mac home network

I am running one MacBook Pro (OS X Lion with Office 2011 for Mac) on an otherwise all PC home network. All the PCs are running Windows 7 and MS Office 2003 SP3. The Mac seems well integrated into the network and all computers on the network, including the Mac, can see and communicate with all the other computers. My one problem is with MS Office. I can only sometimes open and edit Office documents on the Mac from a remote PC. In Word for example I get the following error message: "Word cannot open the document; user does not have access privileges. (\\User\Documents\FolderName\WordDocumentName.doc or .dotx)". And in Excel the error message is: "DocumentName.xls cannot be accessed. The file may be read only, or you may be trying to access a read only location. Or, the server the document is stored on may not be responding."
This behaviour is not consistent - some documents can be opened and edited, others cannot. And I can't see any pattern to which will work and which won't. Although the error messages suggest privileges to be the issue privileges on the Mac and the PCs seem to be set appropriately. Searches of the Web seem to suggest that this is one manifestation of an ongoing problem with Office on a mixed PC/Mac network and the problem seems to have something to do with permissions on the hidden .TemporaryItems folder at the root of the share on the Mac - although I'm not sure that I understand these discussions properly. I have never worked with Terminal and the fixes suggested all take me to places I would not be comfortable going even if I were sure that they are addressing the same problem that I am experiencing. Can someone offer a fix that a Mac novice might be comfortable implementing or at least hold his hand as he goes where angels fear to tread.

Workaround

Hi,
I have a similar setup with mix of computers. For sharing files I use Dropbox and they are immediately updated from one machine to the other. The only limitation is that you need to take care if the file is open on multiple machines, not sure if this is a requirement for you.

Thanks Pigstick for your suggestion. I had a look at Dropbox and, your'e right, it would do the trick. But I would still like to solve the problem I have with the network. Is there nobody who can help?