multimap iterator ,assighment operator problem

[yakovm]

Hello
I work with g++ on ubuntu 9.04

Here is a code from cpp file:

for(subPipelineStrings::iterator pipelineIterator = pipelineRange.first;

			pipelineIterator != pipelineRange.second;++pipelineIterator)

		{

			pair<set<pipeline>::iterator,bool> uniqRes = uniqPipeline.insert(pipelineIterator->second);

			if(!uniqRes.second)

			{

				pipelineIterator = m_subPipelineStrings->erase(pipelineIterator);

			}

		}

Here is a declaration .from h file

typedef  multimap<size_t,pipeline> subPipelineStrings;

I have following error

no match for ‘operator=’ in ‘pipelineIterator = ((subPipeString*)this)->subPipeString::m_subPipelineStrings->std::multimap<_Key, _Tp, _Compare, _Alloc>::erase [with _Key = unsigned int, _Tp = std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, _Compare = std::less<unsigned int>, _Alloc = std::allocator<std:air<const unsigned int, std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >](pipelineIterator)’

Thank you in advance.