On the server, you have to recreate all connections to the data sources you are loading from. Just like the original model designer did in the QV Desktop. For instance:
OLEDB: install the driver for your RDBMS on the server, and make sure the DB server can be reached. The connection string will do the rest.
ODBC: use WIndows ODBC manager to create the necessary DSNs that you use in your script. This requires a bigger effort if you're not into that sort of thing.
Excel and other table files: make sure that those files can be reached via the path specifications in your LOAD statements. Drive letters may get you a few surprises here.
Pay attention to authorizations: the QVS is running under another account than the designer of the document. Possibly this account is not authorized to access network, DBs or other required sources. I would suggest to ask a system administrator for help.
Well, you asked me where in the QMC you can manage your data source connections. There is no such place. You'll have to configure your server envrionment so that it corresponds to the data source specs inside the load script. The 3 tasks in my previous reply are to be executed in the Windows environment. For example, if you specify in your script something like
LOAD A, B, C FROM N:\data\Transactions.xls (...);
then before publishing this model on your server you'll have to make sure that the service account that runs QVS/QVP on the server knows about drive N:, can access the network and has permissions to open the Excel file.
When reloading, QVS/QMC/QVP cannot change anything that is hardcoded in your script (except by passing values in variables). So you either adapt your load script so that it changes data access methods when running in a different environment (for example by way of an $(Include) that insert platform-specific data access parameters) or you change your server environment so that is replicates the data source availability of your development environment.
If the folder containing your excels is shared - on a file server for example - you can leave them where they are. Grant the service account access to this shared folder and QVS can access it like you do in your development environment.
If the Excels reside on your own development PC, then you better move them to a file server.
LOAD statements should contain paths to data sources that work on all platforms, like \\Fileserver\data\Transactions.xls. If you move your QlikView document to the server, no script changes are needed.