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When you load scripts from other sources, for example forums, you have to be especially careful. In 3rd party scripts some of the tabs are often converted to blanks. This has to be fixed before the program is executed. Another issue that can be come up is an empty line with a tab or a few blanks at the end of scripts. This line must be removed, because it always leads to syntax errors. Following this rule is an easy method to avoid and eliminate many of the common problems.