SQL 7 and can't connect

I am very new to SQL.   I've come onsite to support a group of users, they
just happen to know more about SQL than I do, however I have to know these
things. :-)

I have several users who go offsite to work on databases for customers.  
They have laptops which work fine in the office when connected to the
server.  Most times, when a user gets to a remote location he'll get on
their network and try to access a locally stored database.  A few users
have never been able to connect, others only on occasion.

One user took his path statement and rearrange it, putting the path to SQL
in front.  That worked for him.  A few other users tried that and had no
luck with it.

Besides the path being taken into consideration (very long path
statements), if someone were created a new account on a customer's network
that didn't match the one he normally logged in with, would that make a
difference?  I guess I'm asking if that he logged in with Michael here at
the office, and logged in with MW at a customer's site, would that keep him
from being able to access his local database?

I'd be greatful if anyone could help with this, or maybe lead me in the
right direction.  

Systems are E500 Compaq laptops with Win 98, SQL 7 SP1, and VB 6 with all
updates, etc.

Thanks a bunch!