Slow saving of Word documents over WAN

Hello

We have a dedicated 64K Kilostream link to a small remote office connected to an NT network at head office. MS Word97 is run from two local machines in the remote location. However, it can take up to a minute or more to save a document (however small) to the head office network drive. Email services, etc. appear to work fine over the link. The remote PCs have an adequate spec and are running Win98. Any ideas on why file saving should take so long? Thanks.