load application under debug mode 10 records each load tables one by one (probably also in debug) and see where the error incurs Some times Join also cause does it always happen on the same table? if you change the order of loading? do you have the rights to read in the database?
So please check all these conditions else if possible share entire Script so that our folks will help you ASAP.
and have a look at the errormessage appearing when reloading script!
From Qlikviw Help:
This variable determines what action is to be taken by QlikView when an error is encountered during script execution.
By default (ErrorMode=1) the script execution will halt and the user will be prompted for action (non-batch mode).
By setting ErrorMode =0 QlikView will suppress all error messages on failure to load. If script execution is halted due to failure, it will not continue.
By setting ErrorMode =2 QlikView will trigger an "Execution of script failed..." error message immediately on failure, without prompting the user for action beforehand.