Zipcar reported its second quarter after the bell yesterday, and it guided down revenue as well as net income for 2012. The immediate reaction from the street was not pretty with after hours trading pushing the stock down over 20 percent. Beyond the figures and guidance revisions, is a greater concern about Europe. Zipcar CEO Scott Griffith said in a statement that “we faced economic challenges in our UK business.” That’s not great news, given that Zipcar’s expansion plans are European focused right now after a series of acquisitions in England, Spain and Austria. The debt crisis is impacting U.S. companies and Zipcar is a prime example, and despite 21 percent membership growth year over year, taking total membership to 731,000, adding new members just isn’t enough to make Wall Street happy. It wants revenue growth to reassure it that the capital expenditures of expansion are generating enough cash flow.