Even though the code compiles without error, it might still not be correct for C55x. This is mostly because C55x is a "16-bit" target. You may need to adjust the STLport code to successfully port it to C55x. In an earlier post, I said
[quote user="Archaeologist"]Furthermore, C5500 does not have either an 8 bit or 64 bit type, so you must beware using these typedefs. Code using them will compile, but will not have exactly the number of bits the code expects. This may lead to computation errors that are undetectable at compilation time.[/quote]
It is possible that this may be contributing to the problem. You may need to look for every place STLport uses 8-bit or 64-bit types and adjust the code if it truly requires a data type of exactly that size. There could also be porting problems with multiplication expressions that have "int" arguments but the code expects at least a 32-bit result.
You should have a look at http://stlport.sourceforge.net/FAQ.shtml, at question 2.4 "When I switch to STLport in my application, I get errors. Is STLport so bad?"